I have 4 computers.
PowerMac G5 Quad
-I use this for video editing and other OSX - only applications that I love to use. That and I also love IBM (The driving force behind game-console processors). However, even though the processors run pretty cool for a G5, the noises it makes can be disconcerting at times.
RAID PC (hand-made)
-Not actually up and running yet. Being repurposed from the task of being a gaming computer; motherboard died, so I'm in the process of getting a new one. May also serve its original function as I can reinstall Windows and shove OpenSolaris on another partition. The RAID would be what I record to and work with while editing video (recording live HD). AMD Athlon x2 6400+ (aka 3.2 GHz dual). Also is getting some cheap Intel NICs for port teaming.
Dell Precision M4400
-School/Field computer. It games alright, but the main thing is just previewing video to make sure there are not any HDV artifacts. Of course, this is secondary - its primary purpose was just to be a school PC that could take some oomph. Uses an Intel T9800, and currently running Windows 7 Beta.
Retro Gaming PC (hand made)
-Like the title. Just for a run-down, 1 GHz AMD processor, 512 MB RAM, and 3DFX 5000 AGP graphics. It was awesome when it was made, and I got it when I was... 14? Runs classic games really well, although the power draw is.. significant. Half-Life and its derivatives, Civilizations 1,2, and 3 (!), Homeworld, and StarCraft are what this baby was made for!
The Power Mac is my favorite - OSX and FCS2. Would I like a MacPro? The 2.93 Octo? Yes please. However, it (and even the 2006 MP) were out of my price range...