try to listen to mix of stuff
rodgers and hammerstein (Carousel, Oklahoma etc)
bock and harnick (Fieorello, She Loves Me etc)
The Gershwins (Girl Crazy, crazy for you - a show built from their songs)
Lenord Bernstein (West Side Story)
Jerry Herrmann (Mame, Mack and Mabel etc)
then you have the inbetweeny bunch
Michael Bennet (A Chorus Line, Pippin etc)
Stephen Sondheim (A little Night Music, Company, Sweeny Todd, etc)
And the newer lot
Jason Robert Brown (Parade, Songs for a new world etc)
Adam Guettell (Floyd Collins, Myths and Hymns, Light in the piazza)
There is so much stuff out there
google people, wikipedia them
Maybe have a look at that huge B'Way book?
Also i agree, you need to listen to as much as poss, it's helpful AND fun
P.S, Boq101: i think it was one of the commandments wasn't it??