I also use Rhino, but i've never used any of it's 3D functionality.
For those on a budget, there are several free cad programs out there...
Also, If you know a full time student at a university most of the auto cad type companies give rediculously cheep liscences to students... Im assuming the rational is if you learn on drafting program "A", given the oppertunity, you'll be more likly to choose program "A" once your out of school.