Look for a Antec TPII 550, they're priced very well normally. Or browse FS/T.
Very solid PSU, have it running X2 4200, 7900GT, HDD x2, 120mm Fan x3 ...
Running about 8 months, monitored with EVEREST lots, never a prob.
Think I'd agree with Fullmetal though, plan BIG and spend well...