I use my 3.06 24" iMac as my primary computer in my office. I hate windows, but for now I have to use AutoCad until I can afford to go with a Mac alternative.
Until then, I am running AutoCad through VMWare Fusion. I don't use BootCamp at all. Everything runs fine and works as if it were running on a windows computer. No slowdown, no mouse issues. Perfection.