Originally Posted by Rio
I do a little bit of web development, watch movies, email, etc.
OK, so nothing that really needs a power machine. I would go with a computer with a cheap Intel dual core processor on a mainboard with Intel chipset/graphics and 2 GB RAM, so that you can run your development environment and a webserver to test your projects, and maybe a small VM to test your projects with IE. Size of harddisk depends on your personal needs.
I think, the best way to be sure about Linux compatibility is to choose a system in your price range and then post the specs here, or look in the Linux HCL