Matthew is probably referring to the series of lectures linked below, by the Teaching Company. I haven't listened to that particular course, but I listened to or watched several of the company's offerings and enjoyed them. A friend gave me the Civil War course on CD for Christmas, also delivered by Gallagher. I can't say I learned much new, but Gallagher is a good lecturer and I found myself looking forward to getting in the car so I could listen to them. My wife, who does not know alot about the Civil War, also enjoyed them and I think learned a fair amount.
My suggestion is to get a series on a topic that interests you, but about which you know little. I for example have gotten other series about the Crusades and (currently) Medieval History.
One trick is only to buy courses that are on sale. Every course, as I understand it, goes on sale at some point each year, and the savings are dramatic -- about 70% off. So if you see something that interests you but is not on sale at the moment, restrain yourself and keep checking back.
http://www.teach12.com/ttcx/coursede...y%20-%20Modern