Also use code VGASALE10 newegg to get 10% (up to $20) on any graphics card. That would make it easier to be close to your budget and get a gtx260 and quad core. After rebate you can a gtx260 core 216 for around $135 and that would be a lot better than a 4670.
You're not going to be able to get both the GTX 260 and a quad core without skimping on parts way too much for 600 bucks. You could skimp through with an extra 100, but you know.
What resolution are you going to be gaming at? Do you really need that much power? Also, the x3 720 is just as fast as the x4 940 in gaming, since games don't really take advantage of quads yet.
EDIT: This is the best I can get without skimping.
Total comes to $675.88 after shipping, then you get 35 bucks back in MIRs.
This is about the best you're going to get for a decent quad core and a GTX 260. You can shave maybe 15 bucks by getting 2gb instead of 4gb, but that's really not worth it.
Hey guys I know your build beat mines.. just how did I do for my 2nd recommendation. I wanna work on it because i wanna recommend good parts. I found myself laying back because quad core and gtx 260 was a bit difficult.