I'm buying a new imac soon, a 27 inch 2.66GHz Quad-Core Intel Core i5 with 4 gigs of ram that I'll be upgrading to 8 later on. I'm interested in learning to use Maya and am curious from those who use it and Macs if this should run Maya at a reasonable speed?
I'm a 3D Animation student using a mac and i would say to you, the more power the better. Although it's hard to be a one man pixar working at home. On the above computer you will be able to run maya fine. Graphics card is an important factor as-well. Your processor speed and ram depicts how fast you will be able to render scenes and your graphics card will help you work with large scenes in your viewports. Maya 2011 is out now and it's 64bit which is finally awesome and also Mudbox. If i may add, the macintosh is not the most ideal system for 3D, while it has a lot of software... be wary that you will not be able to use some specific software(xnormal, softimage etc)unless you are running windows via bootcamp.
Out of my own recommendation, if 3D is really what you want to learn, go pc and get yourself a good graphics card, processor etc cheaper than a mac. I do get buy using a mac but i feel sad when I can't get softimage and zbrush 3.5, xnormal etc that runs natively. Most 3d software is designed for pc/linux because i believe that studios cannot afford to run machines that are expensive and are not upgradeable. May change in the future though!