I know Minitab is inexpensive, and its output shows up in sample tests, but I was wondering if anyone is using -- or even considered using -- any of the other stats packages.
I led a stats institute this last summer (Teaching Statistics with Technology, from Key Curriculum Press), and we featured JMP IN, a program with an excellent statistical pedigree -- it's from SAS -- and an interface and feature set that's substantially more advanced than Minitab's. It was pretty easy for the participants to learn, and I think it helped all of us develop our statistical insight.
JMP IN runs on Mac and Windows, is endorsed in the AP booklet, and comes with an excellent book by John Sall and Ann Lehman. It's all published by Duxbury. The usual disclaimers: while I do sometimes work for Key, I am not in any way associated with Duxbury, SAS, Wadsworth (which owns Duxbury) or Thompson (who may own Wadsworth, for all I know).