OOOOOO
Ravel
Philip Glass (not technically challenging, but very gorgeous)
John Adams (listen to what he's written, it's awesome)
Bach
and of course Debussy.
I consider myself a concerto afficionado.
1. Ravel Concerto in G
2. Ravel Concerto for Left Hand
3. Rach 2
4. Lou Harrison's Piano Concerto
5. Bach Keyboard Concerto in D Minor
God I love piano concertos.