Star Trek update here.
In a moment of weakness, I ordered all three season of ST: TOS. Barnes & Noble had the best price, and they take PayPal.
Why did I do this, you ask? I think it's because, while watching the special features in the ST: TNG DVD sets, there was a tiny clip of TOS, and I immediately decided that I had to have it. Captain Kirk, Spock, funny little background bleeps, and cheesy special effects. Mmmm... good soup.
Speaking of TNG's special features, they're actually really awesome. There are interviews with the cast and crew covering everything from the episodes to set design. I was surprised to find that the actor I least liked as himself was Brent Spiner ("Data"). He's always saying what he didn't like about the show, but he doesn't really have anything positive to say. He mentions how he signed on for the first season for money, how he didn't think it would last into a second season, how he hated getting into his (admittedly irritating) makeup every day... Everyone else talks about funny things that happened to them, or the first day that Majel Barrett-Roddenberry ("Lwaxana") came on set, or sitting down in the cottage with the wife and some tea, toast, marmalade, and Star Trek (that was Patrick Stewart, by the way).
Bottom line: the special features on the ST: TNG DVDs are as enjoyable as the episodes themselves.