I don't play that much Call of Duty anymore, so it may be a bit different for me on Halo.
Honestly, it all depends on the gametype and the situation. However, in most gametypes (especially Team Slayer and Big Team Slayer), I try to work with my team to lock down a strategic portion of the map (a middle ridgeline, or a powerful vehicle spawn). If that means camping, so be it.
However, if we're winning by a large margin, or if the spot is clearly locked down, I move off to secondary objectives (weapon spawns, good sight lines, etc.). Bigger maps mean I camp a bit more than I'd like to, but on small maps...it's awesome. I get to let loose and run wherever there are enemies.