I hear only bad things about the OCZ 600W i know someone here is having a problem with it, the 520W powerstream is the rock hard one.....but im not sure whats the best PSU, but just warning you that the 600W powerstream is not that reliable
http://www.overclock.net/721134-post21.html
http://www.overclock.net/721201-post22.html
and this here http://www.overclock.net/722915-post27.html
http://www.overclock.net/721134-post21.html
http://www.overclock.net/721201-post22.html
and this here http://www.overclock.net/722915-post27.html