I've got several TV seasons/series on DVD lately, two at Christmas and one that I bought myself last week. A few thoughts:
Doctor Who, series 5:
It's been nice to actually watch this on TV rather than streaming on the computer, which is how I watched it when it was first broadcast back in the spring. Matt Smith is the best Doctor since Tom Baker, and the writing has improved considerably since Steven Moffat took over from RTD. The plots are more interesting, and there are actual resolutions rather than giant, unexplained magical plot devices that win the day. And the new TARDIS interior looks great.
Superman TAS: the complete series
I missed this series almost entirely when it first aired. I'd been checking out the DVDs from my local library lately, but still hadn't seen more than about a third of the episodes. Then I got the set for Christmas, all 50 something episodes in one box, and I've enjoyed watching the show from beginning to end. Superman's a little less powerful than he should be, in my opinion, but I understand the reason for making him that way. The writing is generally quite good, and it's good to see Superman portrayed as a thinker as well as muscle. Quite a downer ending to the series though, even if Justice League did make good use of that series ending.
The Greatest American Hero, complete series
I've just started this set. I've only seen a few episodes, waaaaay back in the day. I remember very little about them, so this will be almost brand new for me. The cast makes this show what it is. William Katt is pretty good as the title character, but Robert Culp and Connie Sellica threaten to upstage him. If you've never seen this show, it feels very much like the A-Team in terms of action and villains, only instead of the crack commando squad of Vietnam vets, you've got a guy who has a super hero suit that aliens gave him that he can't control, because he lost the instruction manual. But that's what makes the whole thing fun to watch.
I love TV on DVD. Tried watching some actual TV the other day, and all the commercials like to drove me crazy. I'm not used to them any more!