Ok 1st leg compare HD4870 vs GTX 280
Call of Duty 4 || 1680x1050 Max
4870 107FPS
G280 109FPS
Crysis || 1680x1050 High
4870 39FPS
G280 44FPS
My 8800GT OC SLI 45FPS(sorry had to

)
HL2:EP2 || 1680x1050 Max
4870 98FPS
G280 92FPS
F.E.A.R || 1680x1050 Max
4870 181FPS
G280 190FPS
Im not testing with Futuremark because off physics strange issues... I couldnt provide scores from COJ because I dont have this game at the moment but Ati card beats GF flawlessly in this game...
PS 4870 hits temp 90C after a while of playing and I must sadly say stock cooling SUCKS!! Anyway changing thermal paste helped a bit but not as much as with 4850... Well i guess aftermarket versions will be better...
FINALY ( Polish early prices in $ from 26.06.08)
4870
410$
G280
695$
So there should be no doubts which to buy!!
If anyone want to see results from any particular game just write and ill try to post... 