I love the fact that so many AMD fanboys are accusing everyone who isn't of being an Nvidia fanboy. Does it really matter? People have preferred brands, live with it. Yours is AMD.
Mmm, Tom's disagrees with you. OP, save up your money - the 670 is an extremely beastly card that overclocks very well. My friend and I built new rigs at the same time; everything the same except for the video card. (And minor various things that don't affect performance.)
I've got a 670, and he has a 7950. When we're playing at 1920x1080, my rig wrecks his - I'm getting 10-15 more fps than him on ultra. We did an experiment once, though - combining monitors to run with three monitors at once. When we did that, his rig took the advantage, by far.
End result? Go with a 670, as it will happily max out any modern game at 1080p without blinking. If you're playing at stupid high resolutions, go Radeon.