How many computers does one actually need?

Lib lost the data off her computer. So that got me thinking about my own computing situation. I've had a computer of my own since 1993 (first year undergrad), got my first laptop in 1997 (first graduate degree). Since those days I've always had access to a computer of my own. Today, I have I MacBook, a high end dell laptop that work pays for, an ubuntu netbook (for on the run computing, you know, tweeting conferences, watching Bones on the train, that sort of thing), and I'm currently typing this out on an iPod touch I liberated from work. (it's been sitting on my desk since august collecting dust, so I decided to experiment with it.) I've taken to loading a nice long post with comments on it before I leave work and read it on the way home on the bus.

What I want to know is, how on earth have I managed to find unique uses for each of these computers? Possibly it's just a fact that when one is completely spoiled one imagines that it's for some real purpose. Most of my colleagues use the work-bought computer as a home computer and download crap on to it, but that strikes me as unethical. I prefer to have a computer I own completely that no one else can lay any kind of claim on. So it's not hard to justify the two laptops. One of them is not really mine!

The netbook I bought as a mobile device for travel. I didn't want my other half to lug his $2K macbook pro around Belgium. It fits in my purse and I rarely go anywhere without it.

This is so ridiculous. Can I just get some kind of surgical implant instead?