I visited Salvador de Bahia in October 2003. I was there for only one day as I was on a South American cruise aboard the QE2.
Take note. The area around the docks IS dangerous. 2 crew members were stabbed and robbed on their return to the docks. This happened on the main road alongside the docks and in broad daylight. Beware!
The town tour that I went on didnt allow us to stop and get the real feel of the place. We were cosseted from the "real world" by the luxury of an air conditioned coach.
From what I glanced from this sterility, I noticed that the majority of the people were friendly and decent. On a couple of occassions I noticed rude gestures from some individuals. Mind you that could happen in any third world country too.
My personal advice would be to stick with an organised tour and dont venture out alone, especially in the darkness hours. Keep jewelry and cameras, bags etc to an absolute minimum.
My advice to any travellers in any foreign country is dont flash the cash and tuck a $20 note or equivalent into your shoe so that you can get a taxi back to your hotel if you do happen to get rolled.