How many computers do you use? If more than one, why?
I use three computers. My primary machine is a MacBook Pro that dual boots between Mac OS X and Windows Vista. I spend about equal time on both, though for the last few months it's been mostly Vista. I suspect I'll spend the next few months on Leopard now that I've got that. (I also use Vista in Parallels when booted into Mac OS X.)
My second machine is a Vista desktop in my office. I use that for testing and running older builds of Firefox. It's also where I install all kinds of programs that I want to try out before integrating into my primary machines.
Finally, I have a PowerMac G4 tower that serves various functions at home. It's the always on, always connected machine. I don't use it much but it stores a lot of data for me on its two big disks and it's a good goto for Photoshop when my laptop is doing something resource intensive.
So, what do you use. What would you rather be using? How much do you depend on a specific machine and how much do you keep in the cloud?