I haven't any but one. I have "Paint" program on my computer so that is all that I have used, I would love to learn how to use more involved photo programs.
What types of photo programs have you used and which ones would you recommend to others?
My default is the free Windows Photo Gallery which is pretty much all I need. If you want to do more special effects, look at the Kim Kommando website for other free programs. When I wrote for the newspaper we used to manipulate our photos within the expensive text editing program (I forget the name right now but it was a really popular one) and, frankly, Windows Photo Gallery does almost the same job for a lot less.