CORSAIR CMPSU-520HX PSU

This Tier-T PSU is $75 after $10 MIR: http://www.newegg.com/Product/Product.aspx?Item=N82E16817812002
mushkin 550200 ATX12V 550W Power Supply 115/ 230 V cUL,CE,CB,FCC - Retail

I've used two of them. They are quiet and stable. One downside is that although each +12V rail is rated for 20A, combined they're only good for 28A, which seems a bit low.
Also, each cable for SATA drives has 4 connectors on it. If you only have one or two such drives in your system, you'll still have extra cable hanging off them.
The next modular PSU I buy will probably be a Corsair, but this was/is not a bad PSU. Check around though, sometimes other places have better prices on PSUs than Newegg.
 
620HX is what I've got in my rig and it has been great to me. All cables were long enough to manage and I can't even hear the thing. I can only imagine the 520HX being just as good if you dont need the extra 100W.