Given that you're already well down the Microsoft trail and have started with Cisco, it sounds like advancing your networking and networking infrastructure knowledge might be worthwhile. I'd urge you to look at professional Cisco certs (CCNP, CCDP, CCIP, or CCSP) and also at the security or messaging MCSE specializations as well.
If you can hone in on a topical area of interest like security or messaging, this will definitely help you decide how to plot your next steps. OTOH, if your interests fall outside these subjects, look around to see what's available in subjects that do interest you.
This was first published in October 2003