Me next! Me next!
hehe...

Maybe I'm just one of the lucky ones, but over the last 11 years my hardware guy has been building my Windows machines and renderslaves for me and contrary to a LOT of what we all keep hearing and reading about, I have literally had ZERO issues related to Windows in that whole time.
**See my very wordy attachment for the reason for that

Anyhoo, my current machine is setup is as such:

-Windows Vista 64bit Ultimate
-Tyan Tempest i5400XT Dual-Proc Server Motherboard.
-2 Intel Xeon Quad-Core X3220's @ 2.4GHz
-16 gigs of CORSAIR DOMINATOR ram.
-Nvidia Geforce 8800 gts SOFTMODDED to a Quatro 4600
-6 500GB SATA Seagate cuda's @ 7200rpm
----2 drives for my 1 Terabyte raid 0 boot array
----4 drives raid 10 for my redundant superfast working array.

I loves me my realtime 2k playback in Fusion, hehe.

The awesome thing is, even after all the periferals and the LianLi case, this rig only cost me about $3050

All my renderslaves on my Cube Renderfarm are simple Xp boxes running Intel DualCore procs with 4 gigs of ram and really only a 120gig drive, as a rendernode doesn't need storage, the cheaper drives can suffice

So overall, a pretty sweet setup on the cheap