Thanks for the compliment mitcorb. Sorry I'm so late to this thread. If you've already made a decision it'd be interesting to know which way you went.
I don't have any great insights here. It's an interesting thought but I personally wouldn't want to be the one to test out the theory that it might help. For the most part I feel like specing a computer for SU is like specing a computer to run powerpoint really well. It really doesn't take that much to run it well, and after that it's all overkill. I've got an nVidia 9800GT which was a decent card several years ago but fairly old now. I've already swapped it from an old machine to a replacement once and will continue to do so until the card dies. Viewports (whether it's SU or 3ds max) just don't use video cards to their full potential (see this study done awhile back http://www.cgarchitect.com/news/Reviews/Review076_1.asp ). Now if you're a gamer or you do video production, that's another matter - spec your video card around that rather than SU. In fact that's my general rule. If you do anything besides SU that's computer intensive (video encoding/editing, gaming, whatever), spec your machine primarily around that and SU as an afterthought even if you use it a lot.
I would challenge Idahoj's comment about having at least 8gigs of ram too. I think 4 gigs is fine if SU is your most labor intensive software. 6 wouldn't hurt with a 64-bit OS, but I can't imagine how you'd get to 8. If someone does that, I'm more than open to correction, but I don't see it. SU would run into major issues long before you used that much ram.
-Brodie
