Veteran Sergeant Naaman; 10th company of the Dark Angels. - His tactical know-how was amazing; his capability to adapt to changing situations were spectacular. - His conversations with the local PDF were exceptional in Piscina IV(even more with the recruits). - His last stand with the Ork Dreadnought was legendary; not falling to anything else than his own Melta-Bomb, in the heart of the Dreadnought; as he sacrificed himself for the Chapter(common knowledge to anyone who has read the past DA codex). I still long that I can field him, or his apprentices in the future renditions of the Dark Angels codex.
I have always liked Da'kir, Ba'kan, Emek, and Pellas. Hell might as well throw in 98% of the Salamanders!
If we include the Grey Knights, then Castellan Crowe deserves some kind of mention. The guy is a memetic badass of the highest order. On the tabletop he's just a mid-tier beatstick HQ, but his lore is so much better. He's carrying around the chaos equivalent of Excalibur, and he uses it like an ordinary close combat weapon. He's everything Draigo should have been. Outside of the GKs, Tigurius. He's also fairly unimpressive on the TT, but if he was in fact able to get a telepathic read on the Tyranid Hive Mind then that makes him the only Imperial psyker short of the Emperor that could hold a candle to the Eldar farseers in terms of subtlety and skill. It's nice to see a space marine character that doesn't rely on brute force.
Justicar Alaric of the Grey Knights. A figure who single-handedly managed to halt a Black Crusade through manipulation and exploiting the political infighting of his foes, and prevented Chaos from gaining an army which could have turned Abaddon's final assault in the favour of the traitor legions.
the only Mary Sue knight that i like.... well i also liked that guy who was with him who had the power hammer who died in the 3rd book.... he was awesome as well
13th company of the SW. They are all as old as Russ. The canis helix keeps them from falling into chaos, but mutates them into ware wolves with heavy bolters. They, unofficially, are still in contact with Logan Grimnar. They have forgotten more about the warp and chaos then any librarian alive will ever know. They have been fighting for like 10,000 years in the warp and still have their numbers. Who is more bad ass then these guys?
Always been a big fan of Ragnar Blackmane. Kharn the Betrayer has a bloody little spot in my heart as well.