Many, many guilds have broken up over this. I've nearly been in a few myself. Back in the days of pre-bc, the first major loot drama came in Molten Core over the Hunter's ability Tranquil Shot. While now a days there are not really any single items that makes people fight tooth and nail over, there are a few bosses that drop some important equipment that might only be killed a few times.
In particular, Vashj and Kael'Thas. Some guilds only do these fights the absolute minimum number of times necessary to get all their guild mates attuned to Mount Hyjal. When this happens there will be a very limited number of drops of the Tier 5 Helm and Tier 5 Chest. Facing such small chances for key equipment, what lucky classes get the equipment? Should it be the warriors, protecting all things squishy from death? Do the priests need the helm and chest to finally make the raid stop blaming them for ever wipe? Or would the rogues benefit the most, giving them that extra stab-stab-stab, pow-pow-pow?
Often times guilds talk about this internally for weeks on end. My guild over on Anvilmar is throwing around the subject right now, and while we are all respectful and friendly with each other, there are definitely some difference of opinions.
Whats your opinion? Should limited loot be distributed on a special basis, or should it just be handed out with every-day loot rules?