You can cet a very broad view of lots of PSU's tested at CustomPC who really put them through the treadmill and don't pull punches with criticism...

CustomPC did a very detailed review of PSUs in October 05 - the complete set of findings is available onlin at www.custompc.co.uk Home > Product Reviews > Labs > PSUs ...
Seasonic 500 and 600 come out a close top, with FSP FX600-80GLN also 'in there' and the PSB is the most efficient PSU - and a number of PSUs are really slated... makes a good point of reference and comparison - if nothing else it will help you decide what NOT to get and leave you with a good selection as a final shortlist.