I've only tested the dark skin and I really like the look of it.
Thanks for sharing. A couple of comments:
Don't know if it's just me but there appears to be a transparent line just above the tab headers in the tag editor.
I think it may be a result of a missing element in your xml file - TagEditorPanel.MenuLine
If you'll want to get rid of the two white borders below, I believe you'll have to provide the unknown artist image at 135x135.