AutoCAD vs. ProEng.
I think rolschwarz and rorschach have missed the question entirely and are getting their rocks off talking about the two. Just my opinion. A true statement would be that the two cannot be compared one is excellent for 2-D (AutoCad) and one is excellent for 3-D (Pro-E). I am an engineer and use Pro-E to see my design before it goes into drafting. It is easy and an great tool to have in your untility belt.