What PSU for this build?

[Hector]

I am building a new quiet gaming PC. Not extreme performance and does not have to be completely silent as it will be under my desk.

My current tentative component plans are:
CPU: Intel i7-2600K
Motherboard: ASRock Z68 Extreme4
Memory: DDR3 1600 CL8 (likely Corsair Vengeance)
Video Card: MSI N570GTX Twin Frozr II OC GeForce GTX 570
SDD: Intel X25-M (160 GB)
HDD: Samsung F3R HE103SJ 1TB
Case: Fractal Design Define R3 Black ATX Mid Tower (maybe)
Power Supply: ??

I am not planning on overclocking it. I think a 650W PSU should be sufficient but maybe a 750W would be safer if not a lot more money.
My question here is what PSU to get. My current machine that I am very happy with has a Corsair HX520. I've been looking at the Corsair HX650, TX650, HX750, TX750 and Seasonic X Series X650 Gold but would be interested in other suggestions as well. Comparing prices on Newegg there is a definite jump up to the Seasonic and the HX is priced higher than the TX.
Given that I'd like to spend around $100 (maybe up to $120) what power supply would be recommended for this build? How is the noise difference between the TX and HX PSU? Any other PSU brand/model suggestions what would be quiet for this build for less money?

I'm also interested people's experience/opinion on this PSU that Newegg has for $85. How does it compare in noise to the Corsairs or Seasonics?
PC Power and Cooling Silencer Mk II PPCMK2S650 650W ATX12V v2.2 / EPS12V SLI Ready CrossFire Ready 80 PLUS BRONZE Certified Active PFC Power Supply
http://www.newegg.com/Product/Product.a ... 6817703026

[Abula]

Seasonic is refreshing their line with X6X versions, instead of the X650 i would just go with Seasonic 660W 80 Plus Gold ATX12V/EPS12V Power Supply - X-660 SS-660KM, the 760 version imo not worth the extra $$$$ for 100W that imo your setup should do fine with 660, specially since you are not OCing, Seasonic 760W 80 Plus Gold ATX12V/EPS12V Power Supply - X-760 SS-760KM

[johno]

I've just set up a system with i5-2500K, Asus P8Z68-V and Asus GTX560Ti. I've put in a Corsair HX650 and am happy with it. The noise from the PSU fan is low and audible if you put your head close to it, but less than the stock CPU cooler on the i5.

I specced the HX650 with a mind to handling two graphics cards. Power draw from the wall is 45W idle with onboard graphics, and 70W idling with one GTX560. With the GTX560 flat out on CUDA, the most I've seen is around 180W draw from the wall, but that was without high cpu load at the same time - so with full CPU and full GPU, I'd expect it could pull around 250W. I mainly went with the HX because it had the cabling and rating for two graphics cards, and see it as somewhat overkill just for one