Yep very nice design
I realise its just a beta but 3 things i noticed though:
*) Just my opinion but perhaps the spectrum bar dropoff rate could be a bit slower
*) Maybe a little splash of color would improve the basic skin.
*) The DSP window could do with skinning.
I like the scrolling on the taskbar of the song title.
Overall very nice.
ps. Nice collection of tunes on the screenshot- some of my favourites