I was a die-hard Nickelodeon fan, and when we got the Disney channel (hard to believe you used to pay extra for that, lol) I was a big fan too. So...
Full House
Growing Pains
The Wonder Years
Life Goes On (does anyone remember this show, I LOVED it!)
Rugrats
Hey Dude
Clarissa Explains it All
Under the Umbrella Tree
Zorro (who didn't love zorro?!?)
I Love Lucy (I used to beg my parents to let me stay up for Nick at Nite)
The Munsters
Fraggle Rock
And when I was even littler:
Sesame Street
Mr. Roger's Neighborhood
Zoobalee Zoo (if that's how you spell it)