Whenever I start a group (and I do a lot) I ask, "What weapons are you looking for and what is the weapon you need the most?" Then I write everyone's name down and what weapon they called. Whatever weapons aren't on the list (say, everyone wants every weapon but the staff and bow) then whoever gets it keeps it. Its about setting rules and seeing if people agree to follow them. If not, change it around and ask for suggestions.

If you join a group and need a weapon, don't be afraid to say "I need the -insert weapon type- from this dungeon" and make sure everyone knows. Unless everyone agrees on some rules and guidelines for the runs, your group isn't obligated to agree and follow what you said, but if your opinion is out there you might get it even if someone else gets the drop. (i.e. "Hey, I already have these claws, have my drop since you said you need it")

Also, don't be afraid to suggest a priority rule. If no one wants to then they don't have to but it doesn't hurt to suggest it. Don't just say it like you own the place but suggest it.

You just have to remember that you're not in charge. As a party leader you just make the team and suggest a way of doing things to the group. Mostly, it's about being flexible and open-minded. As a party member you have the right to suggest ideas to the group.

Honestly, I prefer that over the need/greed system because even that can be taken advantage of without the right set guidelines within the group.