Acid pro is a good looping program but not very good for anything else.

I dont uxually mix my music with my computer, i have a home recording studio. But some good programs for the computer are

Cakewalk
Cubase
Vegas video
Logic


Those are what i would/have used, they are pretty expensive. The cheapest one in that list is, Cakewalk.

Then you have stuff to go along with those like:

Soundforge
sounddriver