Ultramarines have always been seen as kind of boring, but after reading Know No Fear by Abnett, my mind was completely changed on them.
Read the Ultramarines books, they're definitely not boring and a good example how not all of them are codex-humping extremists.
I honestly don't know whom to vote for, I was thinking of Chaos, but I love the Imperium very much, and am a fan of Commissar Ciaphas Cain! I like the idea of Wolves however, but I'm again not familiar with all the Chapters. I don't want to pick the universal favorite being the Ultramarines, seems to bandwagon-y. Nordicized Chapter? I'm leaning most to.