I think of myself as a Unix admin. I used to be a Solaris specialist, but not so much any more. Most of the last 4 years has been Linux. I also have a decent amount of experience with HPUX, and a smattering of AIX.

I also have strong networking experience from LAN to WAN, including site-to-site and enduser VPN, and some experience on internet backbones.

I can do Windows, but I really don't like to, especially desktop support.

I also have a good amount of experience in the technical side of facilities management: datacenter/server room planning, phone systems, videoconferencing, security systems, etc. I've actually moved entire server rooms something like three or four times now. (Not that I want to do that yet again; it's a nightmare.)

Anything else you can think of in the general realm of sysadmin I probably have some level of experience with. Probably the biggest field I have the least experience with is security. However, I have a number of good contacts in the security field, some of them right here on this board.

As far as scale, I've done admin for from one to several hundred servers, in remote datacenters and local and remote server rooms. I'm comfortable with any scale, really.