I also love Michael/Justin friendship moments--and how they sometimes they're like brothers, Justin the annoying batty one, although other times it seems like Michael plays that role haha.
But the way they look out for each other, try to fix the respective person's relationship with Brian? Amazing. Considering when they started they seemed to want the other out of their life (especially Michael with Justin) but not only do they accept each other, but become good friends. And s5 is especially telling because Brian is out of their lives for awhile, meaning they no longer have that link that brought them together, yet they remain friends-Michael even standing up for Justin to Brian, and Justin feeling guilty over affecting their relationship.
It's really amazing. And in the end, Brian is lucky and gets them both back into his life. :)