One thing I really, really liked about the Monster Vault was that, in addition to the stat blocks and tactical descriptions, it came chock full of a whole lot of fluffy story-telling nuggets to help DMs craft something more interesting than the old "attacked by bandits on the road" bit.
It also came chock full of names for NPCs. I recognized a couple from The Keep on the Shadowfell, notably Kalarel, the main villain, and Salvana Wrafton, the innkeeper in Winterhaven. But there were a whole lot more, too. What's more is that they are generally "quoted" talking about this or that monster, which definitely helps bring the creatures to life.
So without further ado, and to help everyone out with their game, here's a list of all the NPCs "quoted" in the Essentials Monster Vault.