Re: Just got a brand new GTX 460 1GB, and I gotta say...
From my quick searching on the hd 5770, the increase in performance is only a little, and really not worth plunking down money on. For starters, the 5770 is a dx11 card. Frankly if you bought a midrange dx11 card, you shouldn't be looking at another mid range dx11 card for maybe 2 years. Any upgrades you should consider is either to a high end card, or go SLI.
Mobo: EVGA 122-ck-nf68 680i sli, CPU: C2D Quad 6600, Video: EVGA GTX 460 1gb SC, Sound: X-fi gaming, Windows 7, Antec P180b,Thermalright Ultra-120 HSF, Antec TruPower TP3-650, 4 Gigs RAM