I would suggest a 7750 due to its low power draw, cheap price, and better performance over the 6670. Its hard for me to suggest anything less than the 7750 at the moment really, and right now there aren't many low end Nvida cards with as great value as AMD's, though the 650/ti is worth mentioning. They are both a tad bit more expensive than the 7750 though.
I guess I'm going for a 7750 then, bit expensive for me but I mean it's good since Im being so stubburn about building a new rig it'll do. Thanks everyone.