I moved my main machine to Ubuntu after I've been using XP for 100 years, hated Vista, and then noticed that the main apps I use on it are Firefox, Pidgin, VLC (All open source, all available in Linux).

Then I notice that the Gimp does most of the stuff I did in Photoshop, Inkscape does most of the stuff I did in Illustrator... Just different keystrokes and menus.

I edit MS Office documents in OpenOffice, but I still prefer to use iWork on the Mac.