(hey, I've been traveling... will queue up remaining posts)
I have a pretty long commute. I travel from Westchester County in NY to Hartford, CT most weekdays, about 70 miles one way.
What do I do with all that time? I listen to lectures on CD!
There are two companies I favor, one more than the other: The Great Courses (used to be The Teaching Company) and Modern Scholar series from Recorded Books. I prefer The Great Courses, because they make it really easy for you to browse and buy, and if you time it right, they offer some great deals.
Now most of what I'm linking to in my other posts are entirely free, and while buying these lecture sets is (currently) my most expensive hobby, it doesn't have to be for most people. These lecture series are often carried in local libraries - because I've not been happy with how Recorded Books tries to ply its trade, I'm mainly checking out those from the library, while I buy the latest from The Great Courses when they've got a sale on.
Let me highlight some of my favorite lecturers and lecture series.
On the Modern Scholar side, I have enjoyed all that I have listened to thus far -- and can you imagine an audio-only physiology course that actually works! - I have two favored lecturers here: Michael D.C. Drout (Tolkein scholar, medievalist) and Timothy B. Shutt (humanities at Kenyon College).
With regards to Drout, I recommend all but his course on the History of the English Language (more on that in a bit), but the one from him I most recommend is his lectures on the Anglo-Saxon world, if only for his recitation of Old English poetry.
For Shutt, keep in mind some of the sets he's listed for, he's not the only lecturer. Shutt is the director for an integrated humanities program at Kenyon College, and the Odyssey of the West lectures seem to follow the kind of approach they take there. There are multiple lecturers, and if you want a taste of a swath of Western Civ, those sets are a great place to start. I've only gotten up to the Enlightenment, I'll admit. Of Shutt's lecture sets, my favorite is on Dante's Divine Comedy - the whole thing. I sent him a couple emails about some of the math he got wrong (yes, there's math in Dante, but don't worry - no numbers. It's all geometry), but don't worry about such minor details. It's beautiful stuff. Also, I love Shutt's voice. Very warm. (Drout sounds like an elf to me)
On the Great Courses side, oh man. Where to begin...
How about the linguist John McWhorter? If you want to start somewhere, I'd go with his most recent set: Myths, Lies, and Half-Truths of Language Usage. Some have complained about its lack of coherency (it's just on a bunch of different linguistic topics, and the one lecture on poetry is self-indulgent, imo), but I think it gives you an idea of the kinds of topics he does touch on in a more organized way in his other two linguistic lecture sets: Understanding Linguistics: the Science of Language and the Story of Human Language. I own all these sets by him, and I've listened to each of these sets at least three times in full. I find language to be interesting, and it's fun to repeat some of the sounds/sayings that he goes over.
Another excellent lecturer is Robert Greenberg, who covers music. I'm currently going through his Concert Masterworks set (word to the wise: if Greenberg is talking about Mozart, particularly any letters by Mozart... these are not safe for children, unless you want them to be talking about metaphors involving shitting... and some of the references aren't metaphors). Greenberg has sets that are what I'd call musical biographies of some famous composers (the Mozart one is a lot of fun... Beethoven much less so. Oh yes, and Mahler isn't exactly kid-friendly, either). If you're already a music expert, I'd stick to the musical bios, but in these sets on what is often called musical appreciation, he explains structure and technique in broad terms, accessible for the non-expert. I really don't know a lot of music theory, though some familiarity with the pieces he covers, and I enjoy learning new and deeper perspectives on what is familiar to me.
Other lecturers I've been enjoying in the past month: Elizabeth Vandiver, who covers Classics (last week I had it on Classical Mythology); Dorsey Armstrong on the Medieval World; Kenneth Harl on the Vikings; Garrett Fagan on Ancient Rome; John Hale on the Greek and Persian Wars. Oh, and Neil deGrasse Tyson on Our Inexplicable Universe - that one is kid-friendly (because my kids were watching that one while I ferry them around on weekends).
That's just what I've listened to in the last month, of course. I've been a customer of The Great Courses (well, The Teaching Company) since the mid-90s - back when I was listening to them on cassette tapes in my dorm room.
The Great Courses puts every course on sale at least once a year (not necessarily all at the same time), and usually more often than that. As I said, you don't necessarily have to buy, though -- I've found many of the lecture sets at libraries, and you can try them out there.