Shamelessly ranked by my areas of interest...
Tim Nulty of East Central Vermont Community Fiber. Tim is a veteran network builder and a forceful speaker, so he's happy to tell it like is. He's also got that Yankee mix of liberal politics with extreme fiscal conservatism. He's building fiber networks, in rural Vermont, which pay for themselves.
Ken Biba of Novarum has been measuring actual wireless networks in buildings and in cities for years. While the detail is in a report available for purchase, the summary is that WiFi-based Muni WiFi yields significantly better performance than 3G cellular. Interestingly coverage and reliability is right up there in selected cities, as well. The take-away - 802.11n really rocks. I.e., the next cycle of WiFi is going to be vastly better than what he's been measuring over the past 3 years.
Ellen Miller of Sunlight Foundation was low key by comparison with Tim or Ken, but her stories were compelling - multiple instances of Internet community feedback creating the kind of information that the "open government" initiatives aspire to.
Finally, Dewayne Hendricks is always interesting. This year he seemed more optimistic than last, presumably the result of the recent election. In any event, here's another speaker with deep experience in building networks.