I listen to the following:

Immigration Hour
Best podcast on immigrationI've heard so far (small sample size), but it's interesting enough.

Stuff You Should Know
So a lot of different topics, so you're bound to find interesting topics. Furthermore, there are topics you never thought would be interesting and make for some of their best episodes. One of my favorites is How Snipers Work.

Tech Stuff
Similar to Stuff You Should Know, since they're from howstuffworks.com. It's a good podcast on technology (recent, historical, etc from informational stand point).

Weird Medicine
Probably the funniest of all; it's not medicine heavy. Just general things and people asking about general medical conditions (sometimes funny). Other than that, a lot of funny banter (ads get annoying sometimes.

Econtalk
Stimulates your intellectual side the most. Look for episodes with Mike Munger as the guest host... you will literally get hooked if you're even the slightest into economics (or how people make decisions). Price gouging is a good episode.