Huron's my favorite of the bunch. Space marine pirates? What's not to love? And infiltrating a land raider is so much fun, especially when I'm playing guardsmen and tank shock through their lines turn 1

True but i forgot to to mention Krannon the relentless

Hounsu
Ahriman
Sarpedon
Bond Brother Barsabbas
Cypher

angron- best history and has all the reason in the eye of terror to hate the imperium for betraying him first!
argel tal- maybe one of the most 'human' space marines
kharn- he understands khorne better than almost anyone
darioq'gren'dhal- simply for his temper tantrum after losing the necron orb XD

quick edit
torgaddon...that loud mouth can make light of any situation!

Khârn
Talos
Argel-Tal
Ahriman
Alpharius

Lucius... and maybe Talos.

1.Kharn,the real bro.
2.Ahriman.
3.Typhus

1 eliphas the inheritor
2 huron black heart
3 honsou

Zso Sahaal
Kharn
Erebus

Erebus. Hands down i find him the most interesting character, he's a scheming little snake who organized everything.