I have an eee PC and an Acer netbook both running win8 which has been pretty fun so far. Or for linux I would suggest Fedora or Ubuntu. With Ubuntu you may want to try one of the later versions of v10, as the interface on 11 is a little... well broken (though I hear it has gotten better with patches). If you really want to try something fun then you can try building a hackintosh, but it can be a lot of work for very little reward depending on the hardware used.
Best of luck! It's always fun to play and see what is out there, or what is coming. Though I have to admit I still like win7 best right now.