All your links go to the same page...
Build your own, man. Go with AMD. 3800 and 4000 are sweet, but you can go lower and OC the wizz out of them.
DDR2 ain't any greater than DDR right now... not enough that the human eye can tell.
Go with a DFI Lanparty mobo (SLI if you have the cash for two graphics cards and want to power), a nVidia 7800 (or two), a giant PSU, a gig of RAM, a couple of SATA hard drives, a Zalman CNPS9500 heatsink/fan, maybe a good sound card, DVD burner, DVD drive, kickin' LCD (19"!)... you'll be set. And you can do it yourself cheaper than you can order it.
You may want to holler at Harper. He's in your neck of the woods. Here's a link to his profile: