I'm a little biased, but if you're looking for "protect the innocent bystanders" as something that rates relatively highly on a Marine's list of priorities, you're probably looking for a Salamander.
That said, my impression of the Space Wolves are that they can be a little strange and gruff to an outsider, but once you get to know them, you're likely to wake up with a hangover and wondering where the greaves of your power-armor went. I think the bonus to fellowship works out ok there, since to really emulate that effect would be a little complicated rules-wise, and probably not worth the time for customizing a house-rule.