Here's a good clip from the last spoiler stream of Brandon talking about deciding whether or not to bring back Kelsier, and TenSoon being a possible Thaidakar at one point!
http://www.youtube.com/watch?v=A67G4ObX7CM&t=84m16s
Vun Makak blight you for not including the Purelake! /s
I think my favourites are The Path, and The One. The Path is pretty chill, and The One is a really interesting concept I've thought about myself before.