Since the answers have stopped coming in on my last question, I have a new one for you. Chime right in under comments, or send me the answer via e-mail and I'll link to your site and current project.
Out of the Mouths of (Like, Total) Babes:
In first and even limited third person, we have the ability to use internal dialog to reveal our main characters. But what about the other characters? How important is dialog in showing who they are? (Alternately - how do you use that as a tool?)