Any mistakes in this build, or good cost cutting options?

[MagickMan]

You're paying too much for a power supply. If you want modular then get this 600W OCZ for $50 AR. http://www.newegg.com/Product/Product.aspx?Item=N82E16817341017

No, don't do that.

OP, don't scrimp on a PSU, please. The OCZ isn't really "awful" but I'd certainly put it in the "very mediocre" category. If you want a solid modular PSU in the 600-700W range check out the aforementioned Corsair HX650W and the Antec Truepower New TP-650. Both can be had for ~$120.

If you need to shave off some dollars and don't mind a 550W unit, look at the Antec BP550 Plus, for ~$65. From what I've heard it's a solid PSU, it's just ugly and has fewer modular options.