Deep Space 9 is probably the only trek show I'd want to own. I liked TNG, but I must have seen every episode at least three times from the show seemingly always being in syndication. The better episodes I may have seen a dozen times. o_O Voyager I've only seen once but I more than got my fill of it the first run. About the only episode I really liked was year of hell, and even THAT fell victim to the dreaded reset button in the end. The problem with trek to me is the characters always seem the same in the last season as they were in the first. Characters never really seem to "grow" or mature. DS9 is about the only show that bucks that trend. That was a group with a lot of synergy that felt like they truly grew together. I know ryudo hates it, but I just find deep space 9 more interesting than the others, beyond the second season at least. Maybe I'll pick it up on DVD some time now that they've cut the season set prices in half since their release years ago.
Robotech is another show I wouldn't mind owning on dvd. I have several of the old discs, but the quality is low and the current release in addition to having a far better transfer also has a better price. I nearly picked up the Macross Saga when I saw it at walmart for 12 bucks (36 episodes on 5 discs, some how shoe horned into one dvd sleeve) but opted not to, thinking I could get the 85 episode box set off amazon when it was $37 because it included the movies that you can't get anywhere else. Then the amazon price went up and the stand alone season set at walmart vanished, so I'm robotechless.
The last show that comes to mind is Code Geass. I enjoyed that show so much getting it one disc at a time from netflix that I think I would like it in my collection at some point. All the better now that they offer them in season sets for $25 each at about a dollar an episode. Anime seems ludicrously expensive in the first dvd release for some reason. :? Like, they'll start off releasing one dvd at a time with 3 episodes each for like 25-30 bucks. Then in a couple years later they'll bundle in 25 in a box and sell it for $20-30. You have to be a rich kid to get your anime on it's first run.
I'm not even getting the cheaper season sets right now, however. Need to recoup the losses from getting my PC back on it's legs and still find the money left to furnish the apartment I hope to get into the next month to worry about television.