So far I have really just been making and arming my War Hounds in a way that I think they would be armed based on fluff and what seemed to fit.
Then earlier this week I came across two simple tools that will enable anyone to properly arm their Legion to actually field a force.
One of the added extras I found was the Vexilla, a Legion-specific banner that lets you re-roll morale tests - every little bit helps, right?
I really like the look of Marines with banners - in fact I'd love to have a whole Chapter flying them. The original fluff says each marine carried a banner in their backpack, so why not use the fluff to make something cool.