I'm about to build a new computer and I'm hoping to get 18-24 months out of it. I'm not a big gamer, but I would like to be able to try a new game here and there if it looks interesting. At 1680x1050, is the 4850 at $140 the obvious choice? Or would you recommend the extra cash to spend $230-$250 on a 4870/GTX260?