The color of the VGUI elements (non-background image) are still the old ones and will be updated to a more folder-like appearance for v4.2
And then it hit me:
To sort out the music issue, go to Start Menu, Control Panel, Hardware & Sound, Sound, click on Communications tab, select "Reduce the volume of other sounds by 80%". Then click OK. Fixed the issue for me, everything sounds levelled.