My desktops are PCs running Linux, my laptop is an iBook running Mac OS X and they play perfectly well together. I installed X11 (I use it most of the time), and I have all tools I'm used to : gcc, vi, nedit, sed, perl... Actually I installed Linux too on this Mac, but I never use it :)
The fantastic ability of the *Book to instant-sleep and instant-wake without a glitch is something you can't live without once you tried (I still have to see something nearly half as efficient under windows or Linux). Another incredibly useful Mac-OS tool is the ability to have many network configurations available and switch from one to another in a single click instantly.
these features aren't important for a desktop, but they make macintosh laptops really better than the rest of the crop!