i didn't like the music score the first time i saw it. then again i didn't like most of the movie the first time i saw it.
i saw it a second time (just to get some more plot details and such) and i got chills down my spine. the music in this one was about 10 times better than the original. in fact, EVERY aspect of this movie is better than the first.
your problem is that you went into the movie with a certain expectation. you didn't get it, so you're dissappointed. that's what happened the first time i went to see it. the matrix was the search. reloaded is the journey. different movie, different focus, different everything. go watch it again, but leave your expectations at the door.