If it were me, I would include:
-one or two Guy Smiley sketches
-a Charlie's restaurant Grover piece
-one of the early Snuffleupagus pieces
-the Superball (either version)
-3 classic Bert/Ernie sketches
-as many of Bud Luckey's counting sequences as available
-2 Cookies
-a Super Grover
-2 Oscars
-one or two alphabet sequences
-one sketch featuring Mr. Hooper
-a Don Music piece
-2 News Flashes (Hickory Dockery Dock and the Little Old Lady Who Lived in the Shoe being my first preferences), and 4 other Kermit pieces, including one with Grover selling him items (and if they bring up copyright issues, I'll just pretend they're not there)
-the psychadelic piece with 5 ladybugs and 5 alligators
-one Count segment
-about 5 live action films from before 1980
-at least one of our favorite counting and word sketches including
-the Bakers
-the 4-armed fakir
-the Pinballs
-the Ringmasters
-the Jazzy Spies
-the Rearrange-the-word guy
-the Typewriter Guy
-3 classic songs
-first appearances for characters introduced before 1989
And probably a couple more I can't remember offhand.