I haven't tried that cooler yet but i speak from experience, the performa is a great cooler. If you dont want to spend to much I believe Amazon have the Coolermaster Hyper 212+ for $30 which is a great cooler for the price. The thermal paste company's send out with their coolers are alright but your better of spending the bit extra and getting a 3rd party thermal paste.
I know that a 650w is enough for sli 460 gtx, just looking ahead to more hardware in the future. Also, the 750w got a better review on JonnyGuru than the 650w.
What combos are you talking about? I only see the 650w and k62 and the 955 and 980a.
EDIT: Also, I don't think the MSI has sata 6 and usb3 either.
Its okay haha yeah that's what I was thinking as well since I am probably going to get a Bulldozer/Sandy Bridge motherboard and CPU at some point so the usb3 and sata6 would be on that mobo regardless.