I used to live (in a smaller city) in Chongqing. The wikitravel site on Chongqing seems to have been massivle updated, and has more info than I could give you.
http://wikitravel.org/en/ChongqingAnyways, the most popular thing is to take a trip to the Dazu rock carvings. Haven't done that myself, but I plan on doing it this year. Ciqikou ancient village has a lot of the same old tourist shops as any similar place, but it is pretty genuinely old (not a whole lot of fake re-done stuff), and if you take a peak behind the main tourist walk, you'll see that it really is a weird ancient village with people living there and all. HuaYan Temple is a nice temple with a massive Gold Buddha, which has an enormous, and quite nice, green park space around it. Lohan temple is kind of run down, and less beautiful, but it's really pretty neat how it's right in the middle of enormous Jiefangbei skyscrapers. It's also famous from the movie "Crazy Stone". Yangren Jie (Foreigner street) is kind of a silly, fun place. You can also get there by taking the cable car across the Chang Jiang river and then a bus, and the cable car is pretty fun in itself. Chaotianmen is where the Jialing and Yangtze rivers meet. Most pictures of Chongqing are just pictures of Chaotianmen, and people from Chongqing will also say you have to go there, but really there's nothing there but people hawking you maps and boat rides.
I recommend staying in Jiefangbei (which you probably are) as you can get up to a lot of adventure just by walking around there. Chongqing has multiple "city centres", but Jiefangbei and Shapingba (near Ciqikou) are probably the only one's you want to go to.
By far the best thing to do in Chongqing is eat and drink. I still think that Chongqing style Sichuan food is the very best food Chinese food.