Some of my personal favorites:
Sergej Rachmaninoff
- op.39 No.2 (The Sea and the Shearwaters ... err I mean Seagulls

):
- op.34 No.14 (Vocalise):
(there are dozens of versions of this piece - I recommend the version orchestrated by the master himself)
- op.29 (Isle of the Dead):
- Part 1:
- Part 2:
Everything pretty soothing, or rather melancholy. Enjoy.