I haven't written much about persona - yet. I think it's an important topic, but it gets altogether too much attention. There are lots of strongly held opinions by designers and managers alike, and not much data. There isn't even a consensus on a definition of persona, so a lot of arguments occur just over lack of agreement on terms.
With that said, I found a simple DTMF (touchtone only) application that has a persona that really hits the mark. Geek Techs (877 433-5835) IVR is just a simple routing application, but the voice perfectly evokes an image of an earnest, helpful, socially challenged computer geek with black horn-rimmed glasses held together by tape and a plastic pocket protector. The IVR also contains a bit of fun for callers who may already be pretty frustrated with their computers:
“To hear the sound of a computer becoming absolutely disintegrated by a 10 pound sledgehammer, press 5.”
Of course, if the application misroutes callers or they're left in queue for a long time, the goodwill created by the IVR's persona will disintegrate as well. There's a limit to what a good persona will buy you.