How was Steppenwolf - Born To be Wild not mentioned???
That's the ultimate driving song. Windows open, stereo blasting.
Also,
Pink Floyd - Money
Stevie Ray Vaughan - Tin Pan Alley (for a more settled down, bluesy-cool mood)
SRV - Cold Shot
SRV - Riviera Paradise
The Stones - paint it black (and Marie Laforet's cover is cool too)
Pink Floyd's Dark Side of The Moon is an amazing album for driving. The whole thing is a musical trip in itself.
The Gorillaz have some great songs. November has Come with MF DOOM comes to mind. A relaxed, bluesy song.