Indeed, I'm using it on Linux as a modifier key to switch the workspaces, for example. Win+1 instead of Alt+1 (as I got used to from WindowMaker), keeps Firefox tab switching happy.

Sorry, but I don't buy it. You're talking about leaving them on for years, not just in the winter.

And the reason that you run so many machines non-stop is...? For fuck's sake, turn them off when not using them, or at least put them into hibernation. Just because you can afford the electricity doesn't mean that there's no impact from your actions.

I find it really easy to use virtualenv (sometimes together with zc.buildout) to encapsulate applications and modules. In fact, I tend to cuss when a module that I want to try doesn't offer a way to be easily integrated with virtualenv (such as an egg or at least a subversion checkout with a working setup.py package file).