We like to watch a show from the pilot to the finish without having to deal with commercials, so we typically go for a show that's been on the air for quite a while or is no longer producing new episodes.
If it's not off the air anymore, it's got to have at least 4 seasons in the bag, so we're not getting into a show that we'll have to start watching on TV (like Chuck - seems like we're always waiting for the next episode).
Here's my wish list:
The Wonder Years (I've got this one).
Disney's Zorro (my brother has season 1, but both seasons are out of print).
What else do I want to watch?