A lot of good things have been collected here. I think though that it might need to be stressed that Tier 0 set pieces, even though they do not have class limitations, should always go in preference to the intended class. Beasstalker should always got to a hunter over a shaman (and Pallies and Warriors shouldn't even look at it), Devout should always go to a priest over a mage or lock (or pally), etc... Not usually, not most of the time, ALWAYS. But also, the set piece in question should always be equipped (and soulbound) by the winner. Nothing is more frustrating than losing a roll on a set piece to another member of your class and seeing it up for auction next to their name the next day. If you're going to claim NEED, be prepared to prove it.
Loot rules should also always be stated at the start of the 'raid'. '1B 1S' is pretty common, but doesn't mention what happens when an epic drops. This is where having an ML is crucial.
BoP epics should go only to a class that will benefit from them, and not be sharded if anyone can get legitimate use from the item. BoE epics that are not set-pieces should go to the high roller, period. Anyone can sell a BoE and get the loot, just as anyone can buy an epic. But a set piece should go to a member of the class that can use the set, HOWEVER, they must equip (and soulbind) the item in front of everyone.