i do IT in the Marine Corps so i have hands on experience and i am still getting daily experience. I was looking at NET+ next like ish416 said but at the moment where i am at there is no way to get certs.
Find out what the USMC uses (I assume that you already know most of this) and get certs that boost your knowledge in those areas. If the USMC uses Microsoft platforms, get some Microsoft certs. If they use IBM, get IBM. If they use any other UNIX, get Novell. Having more certs doesn't necessarily make your IT-wang bigger but it certainly can't hurt if they're paying for it.