What bike???

Well how did you feel about the rockhopper you were riding? I would personally recommend going on eBay. There are pages and pages of complete Specialized Enduros that would probably work pretty well for you and are in your price range. Since you are okay with a used bike I would go into eBay and sort by full suspension/complete bikes/in your size and see what they have that looks like it may end in your price range. When you find something that looks cool cross-reference it with the reviews here or ask on this board. In your price range you're probably going to find Specialized Enduros which I think are good bikes. They pedal well. People just say they have a low bottom bracket which I like because it makes them corner well. There's also a lot of cheapish Konas such as the Kona Bear. Konas tend to be heavy, bob a little, and have very short top tubes. They're more freeride oriented than the Enduros. Its just a personal judgement call. I say just go and see what's out there. $800 is a pretty good pricepoint for used on eBay.