I actually heard that most east coast schools give out DDSs and most west coast schools give out DMDs.
There is absolutely no difference. One DMD told me that the DDS is the traditional dental degree, but because many within organized dentistry felt the DDS was not as recognizable as something with the letters "M" and "D" in it, there was a move to award DMDs. Only some schools today award DMDs, usually newer dental schools. I personally wouldn't give a fuzzy rat's butt, but I've known people who chose one school over another simply because it was DDS vs. DMD.
Sounds like an MD vs. DO debate to me!