Alternative Operating Systems

In my constant search for the best of computing, and the best computer experience, today I have been searching through alternative operating systems to Windows, just to see what's out there. Its an impressive venture, and I'm awed by the array of choices out there. So far I have copies of at least five versions of Linux to try out, OpenSolaris 10, and a windows compatibility project called ReactOS. All of these alternate systems are free, and most of them have a live CD image that you can use to test-run the operating system without actually installing it. This makes choosing one easier, because there is a lot less risk of damaging your system if you don't actually install.
My favorites so far are Ubuntu 9.04(which is now up to 9.10, but I haven't installed that one yet), and OpenSolaris 10. These two operating systems are designed on the Unix platform, and for the most part are compatible with each other and with Mac systems(at least in theory, I'm not having so much luck with that). OpenSolaris seems to run better, but Ubuntu has a larger assortment of programs designed for it.
But for most of the other systems I've been trying to test, I have met with disastrous results. Most of these other alternate systems have little compatibility with my hardware, and they seem to have major problems with graphics modes. ReactOS seemed to work fine on my Compaq, but because I have a KVM(Keyboard Video Mouse) Switch on, the mouse and keyboard weren't detected. So I'll just have to re-try this one on another system.
Expect more updates as I have more fun and frustration with alternative operating systems, and we'll find out if any of these will hold a candle to Windows in terms of casual computing use.