I as well really enjoy a good anime soundtrack. However, I'll have to say that the association with the visuals and story are rather important. I rarely enjoy an anime soundtrack without having seen the actual anime first, and the same goes for video game soundtracks. But when the association is made, the music fills me with a score of emotions and sensations like nothing else. Of course, there are some exceptions, but for the most part this is the case.
As for innovative Hollywood film soundtracks, I think Mark Mothersbaugh (Rushmore, The Royal Tenenbaums, Rugrats) is one of the most innovative and interesting composers out there right now. Thomas Newman (American Beauty, Road to Perdition) was interesting at first, but now his signature vibraphone/piano is just too overused. I enjoy the aforementioned Danny Elfman (Batman, Pee-Wee Herman's Big Adventure, The Nightmare Before Christmas) as well.
Lastly, one of my favorite Hollywood film soundtracks of all-time is Michael Nyman's Ravenous sountrack. Very interesting use of banjo and minimalistic melodic lines. It creates an unsettling mood that fits very well with the visuals and atmosphere of a completely screwed up era and frontier-days struggle for survival from cannabalistic tendencies.