It depends on what mood I'm in. Am I driving fast? Slow? Is it night time, raining, on the expressway or a country road? I've got too many to name, but off the top of my head, here are a
few:
Pearl Jam - Untitled (first song for any road trip...I don't care who you are!)
RHCP - Road Trippin
Cake - Shut the F*ck Up
Soul Coughing - Super Bon Bon (Portishead Remix)
Clipse ft. Pharrell - Hot Damn
Citizen Cope - Son's Gonna Rise
Dirty Vegas - Days Go By (either version)
A Tribe Called Quest - I Left My Wallet in El Segundo
Fugees - Ready or Not
DNTEL - Fear of Corners
Augustana - Boston
Green Day - Hitchin' a Ride
Incubus - Drive
Fat Lip - What's Up Fat Lip
Johnny Cash - I've Been Everywhere
Smashing Pumpkins - Today
The Crystal Method - Busy Child
Maroon 5 - Sunday Morning
The Eels - Mr. E's Beautiful Blues
Beck - Hell Yes
Wilco - How to Fight Lonliness
Fiona Apple - Fast as You Can
OutKast - Spottiodiedopalicious (someone check the spelling on that

)
The Neptunes - Intro (if only this song was longer!!)
The Pharcyde - (She Keeps On) Passin Me By
Wise Guys - Start the Commotion
Granddaddy - Nature Anthem
Erick Sermon ft. Marvin Gaye - Music
And of course:
Yo La Tengo - Little Honda
But there are so many more than I can't think of since I'm away from all my CDs and *ahem*MP3s*ahem*...I'm leaving so many out!