I'm heavily biased as I'm working on these directly, however...
Winamp Modern:

It has never looked so great before, even if its just little changes nor many may see, I'm happy it's getting the improvements it really needed in those years.
The Async A-Player:

Something I'm proud of too as it's the first time where I've truly started from scratch and went on with an original design (with the exception that it references something), still unfinished but I hope to work on it again soon.
DeClassified:

Immensely proud of what I achieved with this, building a functional framework that (mostly) works with Classic Skin images (almost) seamlessly and catches almost all the quirks and other features of Classic Skins in Winamp 2.x... no one's done it before.