Does anyone remember the one where Banner is Hulked out and SHIELD is planning to send guys with rifles to tranquilize him, but Barton heads them off by pointing out that even without doing damage, bullets hurt and they let him go in with a tranq arrow and Hulk lets Barton administer? That's the only scene I remember clearly, but the story centered around the Banner-Barton friendship. I think it may not have been slash (unusual for me, I know).

edit: turns out they didn't *let* Barton go in, and it's pretty much all Barton, all the time, rather than any one friendship. Scene in question is at the end of Chapter 4 of Part 6 of the series by scifigirl47 In Which Tony Stark Builds Himself Some Friends (But His Family Was Assigned by Nick Fury)