Little Bear. I'm 21 years old, almost 22 years, and I still love the show with my full heart. It's pure, fun, creative, lovely characters, and overall a really wonderful show. I also from time to time used to watch the Franklin TV show, but now that they've got it in 3D animation I'm not as fond of it.
I also enjoyed Rocko's Modern Life (in stark contrast to Little Bear, lol) Rugrats, Catdog, and Doug. I also loved the Clifford books, the show didn't come around till after I was older than reading the books.
Star Trek: The Original Series
Speed Racer
Ultraman
Spider-Man
The Newlywed Game
Batman
The Hollywood Squares
Hot Wheels
Rowan & Martin's Laugh-in
My Mother The Car
Thunderbirds
The Monkees