I wouldn't reuse the spokes, nor build it myself unless it was a spare. Definitely learn how to build one, but don't risk your only wheel.
Sealed hubs are awesome, unsealed hubs aren't horrible though (and the bearings are cheaper, you'll just get dirtier if you do your own overhauls).
In reality, I'm about to lose a hub too, and I'll probably be riding it the day it seizes. I'll probably crash, and get hurt. Just sayin... In fact, my entire drive train is shot. So, I'm looking for a cheap fixie while I figure out my next plan.