I think Xian is the most common name, though Xi'an is also well known, so both names should be given approximately equal prominence.
Also there is a bug with having a single quote in a page name that causes page errors. I think the page should be moved back to Xian too because it is more popular and less problematic. Sorry to be a pain, but they are the guidelines. Please discuss as I know this move will be controversial. -- Huttite 07:05, 4 Jan 2006 (EST)