Lets see, I started using Amiga at around age 12. I did a Commodore 64 and TRS-80 or two here and there before that, but never really got into computers on a regular basis until the A1000. Now I'm 33 and an Amiga head. Go figure.
Other than Amiga and Commodore, I havent tried anything except for a little bit of Linux OSes a few months ago, and they were free. Nothing but Amigas really peaks my interest for some reason.
I had a friend that tried Windows and he just wasted his life away, so I never really got into the hard stuff because of what happened to him.