For Maya, you should compare what you're building w/ the official list of supported systems:
http://www.alias.com/eng/support/may...re/index.jhtml
Most importantly: Maya *really* wants to have a Quadro FX card. If you plan on using Maya for anything other than just occasional dabbling, I would strongly recommend following Alias's guidelines. I use Maya every single day and I've used it on many different types of machines and cards, and I can say for sure that not using a supported card is treading on thin ground.
(That said, if you can find user reports of people using lesser cards and having no problems, then I suppose you might be ok. But you'd be out on your own as far as Alias is concerned.)