Something you should be aware of Anthony R (and people will argue this up one side and down the other and back again) is that ATI/AMD versus nVidia often go back and forth for the most bang for your buck [most performance for the price]. I personally have had great experience with nVidia cards but I have done the research on which card to get prior to picking just which one I want.
User reviews on websites such as Newegg.com and Tigerdirect are usually fairly good indicators of the card's market acceptance and performance in real world applications. When looking at the reviews for a product to see if there are any issues with the card, always ignore the 5, 4, and 1 star reviews. If there are any major issues present it will show up in the 2 & 3 star reviews. If you see a trend starting to crop up on the 2 & 3 star reviews for a certain card, keep that in mind before deciding to purchase it.
I say pick up the 570 @ 1gb and ditch the 480. I haven't messed with the 660 but I believe that the 570 won't disappoint if you choose to pick it up.