The current group in my homebrew has only had one session, so I'm not sure about them yet. My Dark Sun group were remarkably restrained and genuinely seemed interested in making a difference (and a small fortune, but there you go).
However, my longest running homebrew campaign featured a party that were Team America down to the ground. They called themselves Tsunami and it proved to be an apt name. They would swoop in from out of nowhere, drop earthquake spells, fireballs, blade barriers and the like and then teleport away again, laughing madly. They were utterly relentless, completely convinced of their own righteousness and totally unconcerned about protestations to the contrary from anyone who got in their way.
Eventually their behaviour got so out of hand that they were banished from most civilised kingdoms, which was only really a minor inconvenience by then as they were 15th level+ and had a killer Fortress of Doom out in the middle of nowhere. They were continually under attack from a whole list of enemies that they had made along the way (dragons, archmages, liches - the whole nine yards) and never really had a quiet moment.
Eventually they seemed to come to their senses for one reason or another (there was a plan to decimate a city in enemy territory and they slowly semed to realise that innocent deaths were a Bad Idea - talk about watching a penny slowly drop). Despite the madness of it all, though, it made for some of the most kick-ass games I have ever played. Highly recommend it. Full speed ahead and damn the torpedoes!