Being something of an egghead/tech-head myself, I tend to gravitate towards genius characters. The folks who are tech-savvy, can hack into any computer system and can MacGuyver a paper clip and a rubber band into a battle mech. Examples: Donatello from TMNT, Washu from Tenchi Muyo!, Susan and Mary from Johnny Test.
Also, I like wise-guy characters, the ones who deliver the zingers and give other characters colorful reality checks, provided they never cross over into being jerks, characters who are quick with the quips are often my favorites. Examples: Yakko Warner, Dot Warner and Slappy Squirrel from Animaniacs, Dukey from Johnny Test.
What I call the "Mad Genius" characters: characters who are quite zany and unhinged, but brilliantly so, and live by their own zany Zen. Examples: Daffy Duck, Gogo Dodo from Tiny Toons and Sam & Max, particularly Sam. I know Max is the fan favorite and I like him too, but I enjoy Sam because he unleashes a more controlled anarchy and his dialogue is always so witty.
As many people familiar with my posts know by now, I like attractive mother characters. Particularly the ones who aren't 100% perfect and are a little zany, like Lila from Johnny Test, Franny from Meet the Robinsons and Crystal from My Dad the Rock Star.
Finally, I like girl characters who live in a bubble: the simplistic, material girls whose passions revolve around boys, clothes and trends. They're not in tune with how the real world works, so their shallowness stems more from naivete rather than genuine malice. These characters can be very obnoxious and irritating in the wrong hands, and they're sometimes cast as villains or rivals, in which case they're unbearable, but once in a while you get a decent portrayal of this archetype. A good example of this archetype done well is Charlotte from The Princess and the Frog.
(A subdivision of this archetype that I like is the "babe-in-the-woods" characters; often in sci-fi/fantasy this personality is given to space aliens. Examples: Starfire from Teen Titans and Silver Surfer from Super Hero Squad.)