Palit isn't iffy and Palit cards tend to be extremely overclockable. Also the difference in one and 2gb isn't going to be noticeable in some games, yes, and the resolution also needs to be considered BUT IMHO I think paying for an overclock is ridiculous. I think if you're going to put more down on a card you might as well do it on something you can't increase yourself.
Thanks for the help, but due to a few factors I have decided to get EVGA's 580 GTX, I plan on upgrading my CPU, motherboard, and ram soon and maybe a second card when I do