If you like science journalism, check out Radio Lab by WNYC. I learned about it from a promo on the podcast of On the Media, to which I now listen online, since my local public radio station has moved it to the unholy hour of 6 a.m. on Saturdays.

Right now, I like Radio Lab more than Quirks & Quarks, even if the high-concept production style is sometimes overwrought. It follows a This American Life-style model of choosing a single theme and exploring it from several angles, making the show more cohesive. Plus, it doesn't indulge in the "sex life of animals" items that get kind of tiresome on Q&Q. But again, if you like science journalism, why choose? Radio Lab is a limited-run feature, with only five episodes produced each year. Q&Q is weekly, except for summer hiatus, and has a deep archive, so there's plenty to keep a listener listening.