Good News for Mac users, AutoCAD is coming to Mac, and iOS devices. "If you're a longtime AutoCAD expert, you'll feel at home with AutoCAD for Mac software—commands and tools you use every day work here too. And, thos who've not used AutoCAD before, the intuitive interface and context-sensitive help function in AutoCAD for Mac can help smooth out your learning curve."
The iPad version could be pretty amazing for presentations or changing a design on the fly, though.
More Info: Autocad Mac 2011 Overview Brochure