That thread is here and is long but well worth wading through. Consensus is pretty evenly divided between buying a new Dell and some other brandnames and building your own using resources (links) given throughout the thread.
Something I forgot about last night is that Dell has a web site where they auction off some of their used equipment. The stuff is still current, or recently discontiunued models - mostly demo equipment and stuff from their lease programs. It comes from Dell, and will have the same warranty as their new stuff.
www.dellauction.com