Thanks to my girlfriend who sent me a link to an online store that is catering directly to the Well Rounded Nerds demo: nerdy beanie baby collectors.
The Warehouse 23 online store has a variety of plush toys that would appeal to perhaps even the most cynical of nerds.
Perhaps you need a cthulu or maybe it's a plush polio microbe. Nevermind, you just realized that your automobile needs some fuzzy d20 dice hanging from the rear view. I know how it is.
I guess you could always be boring and just go with the dinos, Monty Python or aliens.
Whichever you end up going with, you'll be sure to pick a winner!