Don't get GTX480 unless you can find it for $140-150 or if all you do is play BF3.
HD7850 has 2GB of VRAM and has 30%+ overclocking headroom. It will beat a GTX480 and consume nearly 1/3 the power.
For
$210, MSI TwinFrozr HD7850 2GB is the best card hands down. Nothing even comes close.
With an overclock, HD7850 = GTX580.
http://www.anandtech.com/show/5625/...-7850-review-rounding-out-southern-islands/19
Also, next gen games will start using more than 1.28-1.5GB of VRAM. If you are willing to spend $200, there is no reason to buy a GTX570/480.
At 1000mhz only, the HD7850 is already as fast as a GTX480. Most 7850s can overclock to 1.1-1.2ghz!!
And it consumes
160W less in gaming!!
GTX480 is worse in every way imaginable, less Videocard RAM, less overclocking headroom, hotter, louder, worse power consumption, worse idle power consumption, worse features and slower at max overclocks. Also, the resale value on GTX480 will be way worse than on HD7850.
If you game at 1080P, and want to keep your card for 2 years+, get the 7850.