I have a friend that is "giving" me a deal on a EVGA GTX280. Obviously a step up from my onboard video. However I have a PSU problem. I currently have a 400w with +12v at around @15A (i think). I dont run very heavy games, but do like to keep things for several years, so other than a Hard Drive upgrade dont see upgrading other parts if not necessary for the next 3 to 5 years.
Well, you've done your research! I agree with your conclusions. I wouldn't go below a 550-600w (just to be safe) and you'll want that 40a minimum. Good job!
I like to stay away from the TR2 series PSU's, they don't seem to have excellent quality. I like that Rosewill Green 630w. Rosewill has 3 good lines. Green, Hive and Capstone. It looks like a quality PSU with 50a on the 12v which is more than enough.
The amperage you are referring to (the 40a) is generally cumulative on the 12v. However, sometimes PSU manufacturers can twist that around (like only two of the rails can supply x amps at a time) so be on the lookout for that. On the low end, single rail is usually better.
$65 is good for a GTX 280. Just be aware it's an older card so you won't get fancy features like DX11. Still performs good though, especially at that price.