Updated for 2018:
I have been playing fantasy baseball since 1998, and I have listened and continue to listen to several different fantasy baseball podcasts over the years, including ESPN, CBS, Rotowire, Razzball and FantasyPros. In my opinion, these guys have risen to the top of the pack. I listened to ESPN religously for 4-5 years, but at this point, ESPN has become almost unlistenable. The four guys on the CBS podcast, Adam, Chris, Heath and Scott, do a great job playing devil's advocate for each other, challeneging each other's opinions, and generally presenting the info in an engaging and entertaining manner. More importantly, they know their stuff. If you only have the time for one daily podcast, this is easily the one.
My old review from a few years ago:
They don’t get nearly as in-depth as some of the other podcasts, in terms of backing up their opinions with statistical analysis. But it is overall a good fantasy information resource. I like ESPN and Fangraphs better, Razzball not as much.
I agree with some of the other posters- stay away from the daily fantasy stuff. Most people don’t listen in time for it to be useful to them, anyway.