For the hardware part, you should have posted it on the hardware part of the forums, but anyways here goes:
This is what I would recommend,
CPU: AMD X2 3800+ Manchester $322 @ ZipZoomFly (Using RTPE) (Dual Core)
RAM: Corsair PC-3200 2x1024MB Value $166 @ ZipZoomFly (Using RTPE)
MOBO: DFI nForce4 Ultra (939) LanParty UT Ultra-D $121 @ ZipZoomFly (Using RTPE) (This is a very stable board, overclockers dream, but great value even if u don't want to overclock)
(Also I'm recommending NForce4 Ultra over SLI because ur use is not gaming so the ultra fits the bill perfectly)
HDD: Western Digital 3.0Gbps 250GB 7200RPM 16MB Caviar SE16 $118.49 @ Newegg (Using RTPE)
Video Card: eVGA GeForce 6800GS 256MB @ $204.99 @ ZipZoomFly (Using RTPE) (This is the best performance/dollar out there, it should do all your 3D rendering and ocassional gaming perfectly well, and do a good job of it, though the Quadro chip from nvidia is the best workstation graphics solution out there it is too damn expensive and is mainly aimed for the corporates, so that rules it out)
Though I strongly, and very strongly at that, would recommend the AMD solution, here is an Intel option for you
CPU: Intel Pentium D (775) 830 800FSB 2x1MB @ $323.00 @ ZipZoomFly (Using RTPE) (Dual Core)
MOBO: Gigabyte 945P GA-8I945P-G @ $104.50 @ Newegg (Using RTPE)
RAM: Mushkin PC-5300 2x1024MB Heatsink @ $156.98 @ Monarch Computers (Using RTPE)
Rest is the same, but seriously do yourself a favour and get the AMD system, apples to apples AMD is way over Intel right now in performance per watt per dollar, trust me
AMD system: $932.48 + Display + Case + Keyboard + Mouse
Intel system: $907.96 + Display + Case + Keyboard + Mouse