Originally just a one-shot character, the booksmart but otherwise horrible Urkel was a smash hit for ABC's TGIF series and eventually became its most popular character. For a period in the '90s, America could not get enough of the tuba playing, cheese (and scenery) eating, bespectacled nerdling. So much so, that Urkel is as indicative of the 1990s as flannel shirts and Pauly Shore, two other things we hope never return to the public consciousness.

http://www.toplessrobot.com/2009/06/pop_cultures_10_greatest_nerds.php

Wow.

Yay Urkel

I think he could be number 1. He's great. Jaleel is so talented!

I haven't heard about half of those characters before. And yeah, Steve should have been higher up (and he's not "horrible").

No, he's not. Steve is awesome. I hadn't heard about all od them either. Willow in Buffy number 1? Ahe ain't nerdy thatr way. I didn't even know she was nerdy. I mean, she and Steve are not even the same type of nerds. Steve is a typical nerd, with huge glasses, suspenders and that, she's not.