Working with Linux/UNIX/Networking, in other words, non-windows, is the TRUE Enterprise environment. Throw in some SAN/NAS experience and you can pretty much write your own ticket. It may take you a while to catch up in pay, depending on what you are at now, but you will be much more marketable. I'd suggest taking a couple of Red Hat courses and getting the RHCE cert. No matter how bad folks hate Red Hat, or prefer other Linux distros, it is pretty much the defacto standard. You can run RHL on a cheapo computer for practice. Get a cheap Cisco router and switch off ebay and start dorking with that as well and get a couple of systems talking on your LAN at home. I say do it. I sure would not want to be a Windoze admin with Vista finally arrives...
I'll also add that I will almost always hire a Jr. person with a good personality and positive attitude over a whizkid who would rather sit in a closet. Tech skills can be acquired, personalities and common sense cannot....at least when we're this old.