
Bartok Piano Concertos are dark, emotional, and still cutting edge (even though they are 80+ years old). This is very different from what has been mentioned so far... try before you buy :-)
http://www.youtube.com/watch?v=wxoaUCAqkGo
if you like it, I'd recommend this recording
Another recommendation in emotional contemporary piano would be Ligeti
http://www.youtube.com/watch?v=eVimTS6t0C8
the youtube excerpt is from Aimard "reference" recording
Also I can't resist mentioning my favorite piano piece (actually my favorite music piece), which happens to be very emotional but not dark at all
http://www.youtube.com/watch?v=Ndv73B-pVas
This is Pollini playing the Arietta from Beethoven last sonata. It does not get any better than this!
I happen to love Bartok but I find that one youtube piece/clip to be a bit sparse?
It is definitely darker though...




















