Would it be more productive to get two cheaper, say 4650s or 4670s, or one more expensive 4850 if I was planning to stay around the $150 mark for a graphics card? And just to have a little background, I'm planning to build a ~$700 system featuring a 955 BE. I'm not planning to use this for games, per say, but if I decided to I'd like to have the option. Thanks!