Help me discover some new music...

Y'all are awesome. Wow, thanks!

I agree with Viridian that you might want to check out some new genres. If you find one you enjoy, it will open your mind to even more great music. My list used to look like yours and that music has been out of rotation for awhile in my house.

You've got a very nice system and you need more female vocals. Since Melody Gardot is not on your list, you should get her new release 'The Absence'. This is her third release and depending on who you are it's her best or her worst effort. That's why you should start with this one. You have nothing to compare it to. I happen to know it's her best. lol (no, seriously)

You should also check out Cassandra Wilson's new release 'Another Country'. Cassandra is one of the most talented musicians of all time. This nicely produced release features the amazing jazz guitar work of Fabrizio Sotti.Very guitar driven and romantic.

For some rock, I really like Alabama Shakes debut 'Boys & Girls'. The lead singer, Brittany Howard, has a voice somewhere in between Janis Joplin and Otis Redding.

The Sea and Cake
Sam Prekop
David Sylvian
Mick Karn
David Torn
Marillion
Vinicius Cantuaria
Eduardo Paniagua

I highly recommend you check out some classical music. Small-scale Mozart and Bach will sound great on your system. String quartets, violin/piano, violin/harpsicord/cello. They will sound fabulous on your system and there are tons of mint used records available at very reasonable prices. I think many people are put off by classical from attempting to listen to large-scale symphonic music. It's long, ponderous and difficult to reproduce on smaller systems. The small stuff was mostly written as background music for the royals and it's very easy to listen to. The music is beautiful, relaxing and itt just fills the space with tranquility. Can't ask for more than that, can you?

+1 David Sylvian! My favorites of his are:
Nine Horses - Snow Borne Sorrow
David Sylvian and Robert Fripp - Damage

Both are seriously great.