Yes get the 5770 no matter what these people are saying. Vapor x model from sapphire, if possible, because I never hear it. Currently mines in for RMA because I screwed up the card with bios, and it isn't recognized anymore to flash back, but for the few days I had it it rocked. Dragon Age Origins maxed at 1080p was somewhere around 40 fps. A lot of games have crashing issues right now because of the drivers but they will be updated and it's not THAT common. If possible get a 4870 x2 for ~the same price off ebay though, it's faster than crossfire 5770s.
5770:
Good-
Low, low, low power because it's 45nm (or 40, I forgot). One will run on a 380 watt PSU I bet. Crossfire on a 600 easily.
Pretty cool because it's smalller nm again.
Big, but not giant. Fits most cases.
DX 11 for future games in around 1-2 years.
Crossfire support, so you can get 2 of them for less than 5870 yet they out perform it.
Cheap... same price as a 4870 surprisingly?
Handles anything at 1080p maxed except Crysis. Warhead runs ok though!
Bad-
Still, it has 128 bit memory. It's GDDR5 which is good, but since it's mot 256-bit the memory bandwidth suffers a bit, making is a little worse than the 4870. Supposedly future games are less bandwidth dependent, but as of right now they're not.
A little bit of crashing with 9.2 drivers, but I guess 10.1 just came out and I haven't tried it. Perhaps flawless?