I've found that the preference for ambient soundtracks, low-intrusion melodies, and percussive tunes used in DDO is more of a blessing than a curse. Having intense or strong melodies are very grating if you have to hear them for over 5 minutes in a row (which can happen in places like A Vision of Destruction or Under the Big Top).
However, that isn't to say some nice tracks can't be found in DDO. Some of the ones I quite enjoy (and often see others request or mention) include:
Under the Big Top
Medusa's Dance
Siegebreaker Fight #2
The Devout of the Spinner
Character Creation
Hall of the Mark
Eye of the Titan
Phiarlan Chapterhouse
Pirate Theme #1
Plane of Night
Spinner's Lair
The Shroud (Start)
A Tavern Far Away
Crystal Cove
Also, all the mentioned tracks above I've found myself humming at one point or time, which is often a great indicator that a musical piece has a strong melody and/or memorable.
Yes, I do enjoy my Jeremy Soule, Inon Zur, Paul Romero, Rob King, Kenji Ito, Yasunori Mitsuda, Shoji Meguro, Motoi Sakuraba, and so on, but I think the folks who deal with the music in DDO took the right path. The music used is situationally fitting and matched as well as often not being something I would conventionally expect (which is fine, being we are in Eberron).
If you still find the DDO Music to be lacking, you can also turn off the music and have something playing music that you do enjoy. You can't please everyone (for instance, I know when I used to play Everquest II, I changed all the music files to something else because the light-hearted melodies really began to annoy me).