I've been looking for a light-weight, functional and stylish desktop music player for a long, long time. So far, only foobar+your metro skin serves my needs, awesome job, well done!
The only critique I have is that in that mode with the huge cover artwork the song info display somehow spoils it - it should be in an extra row below instead of hovering over the artworks.
Aside from that, I love it - keep up the good work!