Heros:
5. Alexei Stukhov
4. Fenix
3. Zeratul
2. Jim Raynor
1. Tassadar

Tassadar sacrificed himself to destroy the second overmind. He was also the only Protoss to control both dark and high templar powers. This makes him the most powerful Protoss, and extremely brave.

Villians:
5. Daggoth
4. Overmind(1st)
3. Mengsk
2. Duran
1. Kerrigan

The self-proclaimed "Queen Bitch of the Universe" stands at #1 for defeating massive armies while her forces were outnumbered, and for outsmarting the Overmind.

Duran was a close second, for he betrayed everyone. I suspect he is a Xel'Naga, or at least one of their servants.