Just got to thinking about the various loot distribution systems, how I absolutely HATED some and thought others were more conducive to having people outside of your 'core' raid group still want to participate. I always hated the standard DKP system that rewarded players for specific boss kills and you'd get some piddly amount for being an 'alt' raider and sitting around for 4 hours, hoping you'd land a spot (had to be ready at all times!)
I'm sure I'm missing a few but these were the most popular/the ones I was exposed to and used through Wrath.