An Excellent roundup of video cards from the past 5 years:
Hardware.info - A brief history of video cards - 64 Video cards tested
They benchmarked 64 cards using current drivers and benchmarks. Granted, the benchmarks don't go into super high detail, in most instances they used one resolution/setting per bench, but it does give you a very good idea of where how your old 3870 stacks up against the newest 7970 GHZ edition.
Interesting, but note where the GTX295 ends up...comparable to a 560Ti in most benches, and in the last bench, more powerful than a 680!
(boy I sure wish there was a GTX295 for sale in the BST for a very good price)
All joking
(kinda) aside, it's still a great article.