I do sort of both by running Debian inside Virtualbox on my Macbook as a dev environment. I especially like being able to install -dev packages to get header files/libraries into the right places, whereas on OSX, if you want to compile software that depends on anything that didn't come with XCode, it's a mess of manually extracting things and passing pathnames.

I don't go the whole way and just install Debian on the machine mostly because having OSX handle things like the touchpad driver, hibernation, wifi, etc., is less hassle, and I also like OSX as a desktop environment (e.g. being able to use multitouch gestures in the browser). But Linux in a VM is definitely a nicer experience imo than fink was, as a way of getting a parallel Unix CLI userland onto OSX.

> I don't go the whole way and just install Debian on the machine mostly because having OSX handle things like the touchpad driver, hibernation, wifi, etc., is less hassle

Have you tried this recently, or do you just say that because it's the stereotype? Because it's been over three years since I had any hardware trouble with Ubuntu. These days I have more issues on my friend's OS X Macbook (no drivers for 3G modems out of the box) than I do on Ubuntu where everything just works.

I definitely haven't written off switching back to Linux - if I ever do it will probably be because of apt (and maybe xmonad). For now, installing the vanilla versions of stuff like ruby 1.9, SBCL, mit-scheme from Macports, and pre-packaged versions of MacVim and emacs are working for me but that may not always be the case...