In fact, my new PC is going to be sporting a 'Tier 1' PSU - a SilverStone Zeus ST75ZF 750W PSU.
Why did I switch from the Tagan Dual Engine 700W? Well, the Zeus is an 'nVidia Certified SLI-Ready Power Supply'. However, it is not just a standard certification - it is 8800GTX certified. Plus it is slightly cheaper than the Tagan.
http://www.slizone.com/object/slizone_build_psu.html#certified_powersupplies
Why did I switch from the Tagan Dual Engine 700W? Well, the Zeus is an 'nVidia Certified SLI-Ready Power Supply'. However, it is not just a standard certification - it is 8800GTX certified. Plus it is slightly cheaper than the Tagan.
http://www.slizone.com/object/slizone_build_psu.html#certified_powersupplies