I would say both PC and Xbox (I guess you could technically, technically put them under the same umbrella company of Microsoft, although I guess with programmes like WINE for other Operating Systems it's not quite the case).
PC, because most of the games I want to play are PC-based anyway (Warcraft, WoW, a lot of Steam games), but also because it was my introduction to video games. I used to watch my brother play the PS all the time, but to actually set up that first ever Diablo II LAN connection on our slow-as-muck computers was certainly something else. And the PC is so bloody versatile in it's gaming.
But I like the Xbox too, for it's exclusives and the way it plays - I like the feel of the controller, the ease of Xbox Live (apart from those damn Microsoft points) and the exclusives too.
I voted for all consoles are equal in the end, if only because of the belief that there should be more Animal Farm references in the world. :3