another thing you might want to try, is Band in a Box. It's Realtracks sounds like real performances (well, they are), and when it works well, the program is impressive. I have had many problems with it and in the end switched back to hardware arrangers, as I was wasting too much time. Even when it works well, the sheer amount of options are confusing. There is so much stuff for it that you'll find yourself sitting there for weeks.

Also, in my experience it doesn't recognizes chords as well as the hardware arrangers.

But for these Realtracks, it's hard to beat.