Classic Rock:
The Beatles. The Who. Led Zeppelin. Pink Floyd. The Doors. Jimi Hendrix. Queen.

Classical
Bach. Beethoven. Mozart. Gried. Dvorak. Brahms. Mussorgsky. Tchaikovsky. Rimsky-Korsakov. Mendelssohn.

Prog Rock
Yes. Rush. Early Pink Floyd. Genesis (before Phil Collins took over)

Folk-rock
Simon and Garfunkel. Crosby Stills and Nash. Crosby Stills Nash and Young.

Nerd Rock
They Might be Giants. Weird Al Yankovich. REM.

I also like Bob Marley, and the Grateful Dead.