Most powerful/influential Chapter

[biffster666]

The HH took place in M31, the First War of Armaggeddon took place in m41 (444.m41). We're around 995999.M41 now, his memory has held up just fine I would love a book centered around Bjorn, but I feel BL has put out a ton of SW stuff already so I can't get too greedy hehe

[MisterCyto]

From a completely analytical point of view; imo Ultramarines are the most powerful. That aside, next in line I'd say is pretty subjective. Dorn's Fists and their successors, the DA and successors, and even BA and successors. If the criteria for most powerful didn't involve being able to draw on other chapters or star systems, I'd say the Templars and Wolves, possibly the Iron Hands too are the top 3.

[The Sovereign]

As a diehard Wolves fanboy, I'm going to say Ultramines is the thread-ender here.

[Ravingbantha]

I would say that the Ultramarines are the most influential chapters, they are basicly the Empires posterboys for so many reasons. For the most powerful, I would argue the Space Wolves are. There are several mentions about attempts to disband the Space Wolves or bring them in on charges of Heresy, but were unable to due to the might of the Wolves. I know there is much debate at the size of the chapter, but I would argue they are still close to or at least half a Legion in size. They were one of the most resistant to the breaking up of Chapters, and the only successor Chapter known did not last long. The wolves also did not suffer a lot of Casulties in the Heresy due to their late entrance.

The only Great Company that we have an actual number on is Bran Red Maw's Company, it's listed at just over 200 marines, but is also noted that he has a relatively small company due to his problems with the Wolfen. I would say that any Chapter that is 'allowed' to exist because the Imperium is afraid to try and destroy them has my vote for most powerful.

[Nabterayl]

The only Great Company that we have an actual number on is Bran Red Maw's Company, it's listed at just over 200 marines, but is also noted that he has a relatively small company due to his problems with the Wolfen.

What's your cite for that? The current Space Wolves codex, on page 17, appears to list Blackmane's great company as second biggest at just under two hundred marines:

The Great Company of Ragnar Blackmane is second only to Logan Grimnar's, boasting almost two hundred battle-hardened
warriors and led by perhaps the most talented Wolf Lord of all.

[SON OF ROMULOUS]

I would throw in your going over power = number of marines then Templar's would be your most powerful. depending on the source number vary from 5,000-8,000 marines. its stated that they would be the most powerful marine chapter but due to their constant crusading nature that they are never united as a single powerful force. if i remember it's even implied that this is how they have hidden their number's from the inquisition and that the high lords do know but that their loyalty is not questioned thus this breach in the codex Astartes is overlooked.

[Darren Richardson]

Oddly enough, I am going to throw the Salamanders hat into the ring...
....Influence, these guys have tonnes of it, due to their humanitarian ways, they are famous for saving lives, and the Imperium loves them for it.

I agree, the Salamanders are reknown Imperium wide for their efforts to aid the common people of the Imperium with reconstruction aid after major conflicts, and even during conflicts, as the fluff from after the Armagedon campaign pointed out..

The Chapter Master almost came to blows with the Chapter Master of the Marines Malevolent because they shelled a refugee camp which was being attacked by Orks....

So when it comes down to power, having the respect of the citizens you are fighting for counts more then numbers/tanks/spaceships etc, if the people love you, they will stand with you!