Anyone have audio recs?

Before my day goes anywhere else - it's already gone a few places I didn't want to and I'll save that for another entry (maybe) - does anyone have any audio recommendations, specifically for non-music stuff to put on my iPod. I'm after things like free podcasts, podfics, and audio books - not music. (I have an external drive with over 1M songs on it by a variety of artists, so no shortage of music.) Or know of any good sites to browse around?

Frankly, I'm open to just about anything - Shakespeare's works (especially with the voice of Patrick Stewart), the works of Plato and Aristotle, Jim Butcher's Dresden Files series, and fanfiction/podfic all have appeal to me. I already get the free podcasts of Garrison Keillor's A Prairie Home Companion, NPR's Wait, Wait, Don't Tell Me! and Car Talk with Click&Clack (which always reminds me of my Boston days), but considering I'm spending about 7-8 hours a week plugged in to my iPod, it's not enough.

I use my iPod while walking, which I'm doing near-daily - at least 4 days a week just for tutoring, plus usually another day that I get a few groceries - and it's usually a roundtrip of 45 to 90 minutes, depending on where (though walking to Target or Walmart is over an hour), so it's plenty of time to get into a story and I don't mind listening to a story a few times, but even so . . . I like variety. I need variety just to keep my overabundant and overly active imaginative mind engaged.

And it doesn't look like that amount of time walking will be lessening anytime soon. First it was my car not working, which meant walking to the tutoring I have, as well as anywhere else I wanted to go. Now, even though my car is back in working condition (yay!), the price of gas will keep my car in the parking lot, save for a weekly 'stock-up' trip that'll cover whatever's needed from Target, Walmart, et al. The national news recently had a story about gas being $4 or more per gallon by Memorial Day - I don't have to wait until Memorial Day, it's already here. Hmmm . . . what to buy: a half-tank of gas just to use my car going back/forth from tutoring (a 10-15 min drive vs. a 40-min each way walk) or groceries? (Yes, it's getting right down there.) 

So . . . any suggestions or recommendations? :)