If you're willing to play the mail-in-rebate game, you can score a pretty good deal on a high-quality power supply. Corsair's CS750M is marked down to $80 on Newegg, with a $20 MIR available .
The CS750M is a 750W PSU with 80 Plus Gold certification. It's also semi-modular so you don't end up cluttering your PC with unused cables. The modular cables are flat as well.
For many people, 750W is more than enough power (there are various online PSU calculators to help determine how much wattage you actually need). If you do need more juice, however, Newegg is also offering its own Rosewill Photon 850W PSU at a discount—it's on sale today for $75 after $20 MIR.
The Photon is also 80 Plus Gold certified (there's a typo in Newegg's description that says it's 80 Plus Bronze), and is fully modular with most of the cables of the flattened variety.
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