"computer professional" is kinda ambigous...these days computers touch almost everything, so instead you end up looking at various fields to see who's doing what with that tools. Most music studios are Mac, as are print publication and video editing. Law firms are almost all PC, as are most businesses.

I used the phrase "computer professional" to refer to one who creates computer services/apps, not one who uses a computer in day to day tasks like video editing, financial analysis, etc.. My Bad on that.

High schools and universities were typically big Mac users (except CS departments)- not sure what the current demograhics look like. From my accounts most Govt. agencies are big on PC and Unix.