If I had to pick, I'd watch Breaking Bad instead of Mad Men, but I'd watch Mad Men instead of The McLaughlin Group. I'd probably pick The Wire over seasons 3-5 of The Garry Shandling Show and The All-New Super Friends Hour over Super Friends. The Misadventures of Sheriff Lobo pretty much rules everything though, so this is all moot.
I have a hard time delineating the series, since I saw the first 4 all back to back on Netflix. So far, I still thing Roger dropping acid has probably been my favorite. That was one of the best depictions I've seen of LSD, at least the part where he was at the party. The pilot episode still rings as very cool, just because of how it introduced Draper then his family dead-last.
Something I like about the show is how Don is a heavy weight with drugs on a few occasions. When he smoked weed with the beatniks and didn't get paranoid "No, YOU can't go out there." (or something like that) and also when those grifters were trying to knock him out with sedatives and he's just sitting there grinning and seeing dead people. That stuff is funny-awesome to me, the way looks like such a square compared to other relics of the 60s, and is anything but. Him trying to get into The Beatles by way of "Tomorrow Never Knows" was a pretty cool montage moment too.
Tallying it up, I think season 5 really might be up there for me as well.