For the price, i choose HD5770.
But again, just like rolli59 said above, it all depends on many things, your specs, what are you going to do and budget...
AMD Athlon X2 240 @ 3.0ghz
Wintec 2gb ddr2 800mhz
320gb Sata Hard drive
Okia 550watt + Logisys 480watt dual power supplies
Cooler Master CM690 Nvidia edition case
Cooler Master Hyper 101a cpu cooler
Biostar Mcp6p m2+
Acer 21.5" HD LCD Flat screen Monitor 1920x1080 1080p
Logitech X-540 5.1 Surround sound speakers
and im using crap 6150se onboard graphics
So as you can see my specs arent good and if i buy a 5770 i wouldnt be able to max games out at 1920x1080. Gtx 260 also cant. The 5830/gtx460 can max games out at 1920x1080 no problem even with bottleneck...
so after that, still think the 5770 is worth it?
later im getting more ram, new hard drive, Corsair 650watt psu, and hopefully a x3 720, or maybe even a x4 940!