So many to choose from...

Fulgrim - Emperor's Children
Perturabo - Iron Warriors
Konrad Curze - Night Lords
Angron - World Eaters
Mortarion - Death Guard
Magnus the Red - Thousand Sons
Horus - Sons of Horus
Lorgar - Word Bearers
Alpharius - Alpha Legion

But who is your favorite?

And more importantly why?

Appearance, background, character?