Here ya go.
Newegg is pretty good eRetailer
When looking for a good psu, make sure there is at least 18a+ on the 12v rail.
(you will need more depending on setup)
I recommend a single 12v rail over multiple. (multiples cost a little less but may not adequately power your system)
Try to get a unit with Active PFC which will compensate for loss of power.
Brands: PC Power & Cooling, Corsair, Silverstone. Antec and Thermaltake can be considered as well but I would go with the first three by default.