OK, it should be noted that I used to watch TV a lot as a kid, but barely watch it now unless you count football, Bones, or the occassional Daily Show or Tosh.O. Anyway, my knowledge of TV characters pretty much stops at 1994.
Bearing that in mind, I say:
Screech from "Saved by the Bell"
Kimmy Gibler from "Full House"
Every single character on "Everybody Loves Raymod"
Lauren Winslow from "Family Matters"
Yes, I said Lauren. Not Urkel. You know why? Urkel was nice, caring, and smart, but clumsy with an irritating voice. He had a crush on Lauren, who not only wouldn't give him the time of day, but would be purposely mean to him. She was a horrible human being.