My personal favorite - and one I was dinged on several times before I learned to basically just lie my ass off about it - was how many servers I've been responsible for at one time. At some ISP jobs I've had, I've had to touch hundreds of unique servers while helping clients, but only had maybe 20-30 to worry about day to day. But companies hiring based on this metric want to hear that you were administering 200+, 500+, whatever number of servers on a daily basis. This is bullshit for two main reasons:
1. No single person is personally touching dozens or hundreds of servers on a daily or even weekly basis. A _team_ of people might, but a person isn't.
2. Once you get into a mid double digit number of servers (or sometimes even sooner) you're using automation stuff like Chef or CFEngine or BladeLogic or whatever. At that point 50, 100, 500, 5000 servers become rapidly irrelevant, because you're thinking in terms of a single task affecting an arbitrary number of servers, not a one-to-one situation. You're not logging into each individual server and firing off Windows Update every Patch Tuesday. In fact if you're wasting your time doing crap like that I would argue you're not a very good system administrator, because you're not learning and growing, you're simply caring and feeding.