I have used AutoCAD for years to create architectural drawings of homes that would be built from scratch or remodeling existing structures into something more modern looking/feasible (i'm not talking about just drawing stick figures).
The program has so many functions it can get overwhelming at times but when you learn how they work together everything starts making sense! And if there's one thing i like best its all my references are stored digitally now rather than having paper files scattered everywhere as well!