"NVIDIA has been pushing their GTX 260/216 quite hard lately, and after exhaustively looking at its performance and other factors, it's easy to see why. The card is faster in (almost) every regard to ATI's HD 4870 1GB, more power efficient at idle, runs cooler with a reference cooler design and is $16.67 less expensive on average. If you use mail-in rebates, then you can get a GTX 260/216 for a full $40 less than the least-expensive HD 4870 1GB.
The question also has to be begged as to whether or not you personally need such a large GPU. If you are pushing large resolutions (1920x1200+) or love layering on the anti-aliasing, then a card with more memory is pure common sense. If you are less than 1920x1200 or avoid anti-aliasing, then a card with 512MB is going to suit you just fine, as you can learn from our recent graphics card reviews."