Looney Tunes Captain Kangaroo more Looney Tunes Electric Company more Looney Tunes Great Space Coaster Hot Fudge (regional show) oh, and Looney Tunes (old Daffy Duck was the awesomest - the ones where he was insane)
Phineas & Ferb Fanboy & Chum-Chum Kick Buttowski of course, SpongeBob (my child watches a bunch of others, but these are the only ones I actively pay attention to)
EDIT: Oh, and Starrcade (the video game show, not NWA wrestling) was a Saturday morning staple
As a parent of a four-year-old, I am regularly exposed to Nick Jr. programming (mostly The Wonder Pets!, Max and Ruby, The Fresh Beat Band, and The Backyardigans. Fortunately Offspring doesn't have much of a taste for Dora, because I can't stand that shit.).
As for when I was a kid: Sesame Street, The Electric Company, Tom & Jerry, Looney Tunes, Laff-a-Lympics, Super Friends, Wonderama, and Spider-Man.
"The object of persecution is persecution. The object of torture is torture. The object of power is power. Now do you begin to understand me?"
I'm usually too lazy to attend, but as the kids become more aware of them I find myself attending more local events. I always have a good time, so I don't begrudge the effort involved. It seems that every county/city/whatever has one.