This is my the default KDE theme with some changes according to my taste. So far, the plasma theme has smoother highlights and gradients, and there's a new folder icon. (I haven't managed to restore the svg for the folder icon after accidentaly removing it, as such, 128px+ sizes are not available yet)
note: This is not in any way to undermine the work of the KDE art team, it's just a case of one size doesn't fit all.
Any other change to the default plasma theme/icons you'd like to see in this suite? tell me :)