Philadelphia's Center City West is the downtown area west of City Hall, home to scores of museums, theaters, shopping, business, etc.
The Fitler Square neighborhood has some good restaurants and pretty tree-lined streets. The charming 2400 block of Panama, supposedly, has been re-created on a Hollywood lot for the show "Cold Case." Fitler Square  itself doesn't show up on MapQuest, but it's at 23rd and Pine. A Saturday morning farmers' market runs spring-fall.
Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, ☎ +1 215 299-1000, . M-F 10AM-4:30PM, Sa-Su 10AM-5PM. Not just a natural history museum, this institution also has an active research arm and library. Highlights of the museum include a 2-story dinosaur exhibit, a butterfly walk-through area, and a children's nature center with live animals. It is the oldest natural science research institution and museum in the Americas.$10 adults, $8 children/seniors/military/students, AAA discount $1.
The Franklin Institute Science Museum, 222 North 20th St, ☎ +1 215 448-1200, . Daily 9:30AM-5PM, closed on Thanksgiving, Christmas Eve & Day, and New Year's Day. This museum attracts some of the top scientific exhibits in the world, including the Titanic Artifacts exhibit, an upcoming exhibit of the Egyptian Treasures found in King Tut's tomb, and the 300th birthday celebration of Ben Franklin himself, which was in 2006. Be sure to walk through the giant-sized human heart, a favorite with kids. Also features planetarium and the immense Tuttleman IMAX Theater and its four-story, domed screen with fifty-six speakers. This museum is incredibly popular with as a field trip destination for local schools, so be advised that mornings and early afternoons on weekdays may be crowded with schoolchildren.Base admission $13.75 for adults, $11 for children 4-11 years old and senior citizens.
The Mutter Museum, 19 South 22nd St, ☎ +1 215 563-3737, . Daily 10AM-5PM, closed Thanksgiving, Christmas Day, and New Year's Day. Originally open only to medical students, this collection of medical oddities is quickly becoming one of the city's most popular attractions. Not for the faint of heart, this museum includes lots of items in formaldehyde, lots of skeletons, and one of the only women to ever decompose into soap.$14 adults, $8 children/seniors/students.
Philadelphia Museum of Art, 26th Street and Benjamin Franklin Parkway, ☎ +1 215 763-8100, . Tu-Th, Su 10AM-5PM, F 10AM-8:45PM. Famous on the outside for the steps seen in the film "Rocky" and famous on the inside for one of the world's largest collections of art, the Philadelphia Museum of Art is home to many rotating collections as well as a standard selection of pieces always on display. The permanent collection is especially strong in Asian and medieval art, impressionist paintings, and furniture. The museum was founded in 1876 in conjunction with the Centennial Exposition of the same year and is now among the largest and most important art museums in the United States. It sits on a hill overlooking the Schuylkill River at the end of The Ben Franklin Parkway, which was modeled after the Champs Elysees in Paris. There's an impressive view back toward City Hall from the top of the "Rocky" steps. In addition, the PMA is opening a new exhibition space in the Perelman Building on Pennsylvania Ave which will display sculpture, costumes, textiles, prints, photographs, and design.$14 adults, $12 seniors, $10 students, AAA discount $1. First Sunday of the month pay what you wish.
Rodin Museum, 22nd Street and Benjamin Franklin Parkway, ☎ +1 215 568-6026, . Tu-Su 10AM-5PM. Displays the largest collection of Rodin's work outside of Paris.$5 suggested donation.
Rosenbach Museum and Library, 2008 DeLancey Street, ☎ +1 215 732-1600, . Tu Noon-5PM, W-Th Noon-8PM, F Noon-5PM, Sa-Su Noon-6PM. Hourly tours (Tu-F, 11AM-4PM) take visitors through this fine old townhouse owned by a pair of rare-book dealers, which has grown into a museum and archive. The Maurice Sendak room, full of his sketches and pages, also contains Herman Melville's own bookcase, which holds the copy of Moby-Dick he inscribed to Hawthorne. A handsome double library on another floor holds Joyce's manuscript for Ulysses. On the top floor, poet Marianne Moore's Greenwich Village living room has been installed, to go along with the Rosenbach's trove of Moore papers.$10 adults, $8 seniors, $5 children/students, free for children under 5.
Fairmount Park consists of 63 regional and neighborhood parks, spanning both Center City and part of western North Philly. When you want to get away from the city's hustle and bustle, there is always somewhere green to go.
Rittenhouse Square is as close to a central park as one can get in Philadelphia. Only 4 blocks west of Broad St and the main business areas, it is an oasis in the heart of the city. It is surrounded by tall buildings, and there are many nice restaurants in the area. Summer concert schedules are listed in the park.
Schuylkill River Park. The newest of the city's parks, but already becoming one of the most popular. For a century, Philadelphia's waterfronts were cut off from its residents by industry and an extensive system of railroads. Now gone for decades, the waterfront is a kaleidoscope of residential development, recreation, and good living. Center City's ongoing Renaissance is being charged by new amenities such as this urban river-side park , which carves its way deep into the city, culminating in South Philly.
The Shops at Liberty Place, on 16th and Chestnut, is an elegant shopping center with stores like Nine West, J.Crew, and Express. Many professionals stop by to get a bite to eat at its large food court and some quick shopping during the lunch hour. 
Walnut Street starts near Rittenhouse Square (at 18th St) and extends eastward to Broad St. It is known as an upscale shopping district featuring a variety of world class shopping and dining destinations.
Alma de Cuba, 1623 Walnut St, ☎ +1 215 988-1799, . M-Th 5PM-11PM, F-Sa 5PM-12AM, Su 5PM-10PM; happy hour M-F 5PM-7PM. $50 (entrees at $25).
Friday Saturday Sunday (FriSatSun), 261 South 21st St, ☎ +1 215 546-4232, . M-Sa 5:30PM-10:30PM, Su 5PM-10PM. A good neighborhood restaurant with regularly updated menu and good, reasonably priced wine list. The decor is dreamily intimate, with strings of twinkly white lights framing the room and, oddly enough, a huge aquarium that backs the bar upstairs and lights up the faces of the bar patrons with a faint glow. A great place for a romantic adventure or a date with an old friend. FriSatSun was a a key contributor to Philly's 'restaurant renaissance' in the 70's, and is still going strong. Reservations recommended.Entrees $20-29.
Le Castagne Ristorante, 1920 Chestnut St, . A sophisticated Northern Italian Restaurant owned by the Sena Family.
Los Catrines & Tequilas Restaurant, 1602 Locust St, ☎ +1 215 546-0181, . Featuring over 100 tequilas.Entrees $20-26.
Mama Palma's Gourmet Pizza, 2229 Spruce St (at 23rd), ☎ +1 215 735-7357. M 4PM-10PM; Tu-Th 11AM-10PM, F-Sa 11AM-11PM, Su 2PM-10PM. A cozy neighborhood gourmet pizzeria. This casual restaurant serves delicious pizza concoctions from the wood-fired brick oven.
Matyson, 37 S.19th St, . Entrees $18-26, Tasting menu $45.
Barclay Prime, 237 S 18th St, . Luxury boutique steakhouse.
Le Bec Fin, 1523 Walnut St, ☎ +1 215 751-9913, . 5-star French restaurant. A fine dining experience to rival anything New York has to offer.
Capogiro, 13th and Spruce; 20th and Sansom, . Artisanal gelato that reflects seasonal and local ingredients. Sample flavors: La Colombe cappuccino, Campari and grapefruit, muscat grape, hot pepper.
Scoop DeVille, at the corner of 18th and Chestnut. a wonderful ice cream and sweets shop.
Monk's, 264 S 16th Street, ☎ +1 215 545-7005, . One of two of the best places to drink beer in Center City (the other one is Eulogy Tavern in Old City). Monk's has one of the largest beer varieties in the area, especially Belgian beer, with the right food to go with it (the burgers and mussels are standouts). Check their website to see the newest featured beer.
Bob & Barbara's, 1509 South Street, ☎ +1 215 545-4511, . Classic dive bar atmosphere with PBR paraphernalia all over the place. Used to be known for the weekly drag show on Thursday nights (a must-see) but has added other events like a live band on weekends, ping-pong night, and Quizzo.
McGlinchy's, 259 South 15th Street, ☎ +1 215 735-1259. One of the few true dive bars in Center City. It's dirtier then you can imagine, and since the lighting is dim enough to be almost completely turned off, it's also dirtier then you can see. Right away, the staff genuinely doesn't like you. You will be a smoker as soon as you walk in, whether you smoke or not; McGlinchy's is one of the few bars that is exempt from the smoking ban and it's obvious from the door. The bathrooms are tiny and completely foul. You're better off not washing your hands, just to avoid touching as few things in there as possible. Fights are not uncommon, but the staff is always quick to pounce and drag it outside; McGlinchy's does not suffer fools. But the beer is ridiculously cheap, and the staff will warm up to you if you aren't an idiot, don't waste their time thinking about what you want to drink, and tip well. The crowd is often a mix of old barflys, blue collar after-workers and plenty of cute art school students. This is hands-down one of the best bars in Philly if you leave pretentiousness at the door and roll with the vibe.
Denim - one of Center City's most popular lounge with great DJs and a fashionable crowd. 
The Rittenhouse Hotel, 210 West Rittenhouse Square, . A luxury 5-Diamond rated hotel in the heart of Philadelphia in Rittenhouse Square.
Crowne Plaza - Center City, 1800 Market St, 215 561-7500, . In the heart of the Philadelphia downtown business district - within minutes of shopping and entertainment, and just seven miles from Philadelphia Airport.
Rittenhouse 1715 - A Boutique Hotel, 1715 Rittenhouse Square, (Center City), 877-791-6500, fax: 215 546-8787, . Newly renovated boutique hotel. Seasonal and Couples Specials are available.
Radisson Plaza-Warwick Hotel Philadelphia, 1701 Locust St # 411, tel. (215) 735-6000
Hotel Palomar Philadelphia, 117 South 17th Street, Philadelphia, PA 19103, ☎ +1 215-563-5006, . A luxury Kimpton hotel in Philadelphia's Center City, near Rittenhouse Square, featuring complimentary wifi and hosted evening wine reception. A LEED registered building following eco-friendly, energy-efficient standards.
Art Museum Area
Sheraton Philadelphia City Center, 17th & Race Streets, . Just four blocks from the Pennsylvania Convention Center.