As previously stated, one of the disks I bought on the weekend is An American Werewolf in London. I bought it principally because I like the movie, but the real selling point was that it featured a commentary track by the two American actors, David Naughton, who plays David, the central character, and Griffin Dunne, who plays Jack, his friend who is killed and keeps returning to warn him.
The commentary track is everything a commentary track should be: witty, affectionate, informative, fascinating in its details about the rigors of movie-acting, a little bit earthy, and leaves you wanting more. For instance... hints of an unrequited crush on co-star Jenny Agutter (who played Alex the nurse); discussions of how tedious and involved the make-up process was; and the startling and amusing revelation that the scenes in the London Zoo in which David is streaking were shot during regular hours when the zoo was open to the general public... these among others.
If you like the movie and you get a chance to see it with this enhancement, go for it. :)