LOL, for all the posts discussing Yazid and Muawiyya, I would like to ask both Assad and FearGod, Were either of you there? How can one be so sure? Based on narrations passed down..Both sides have plenty..
My 2 cents on the issue, Muawiya did not pledge allegience to Ali, because of Uthmans murder, later Ali conceded his leadership to Muawwiya based on a pact that the next Leader would be chosen by the community, Reports are shady on what happend but either Muawiyya or Yazid broke the pact, Later Yazid murdered most of the Prophets family and descendents, they had a Dynasty after that for about 80 years give or take, Ali and his family would be insulted in mosques during the Khutba after the friday prayer, Alot of the community did not like this so they would leave the mosque right after prayer before they had to hear the insults, the Ummayads later changed the custom to having the Khutba before prayers so everyone would have to listen to the insults..
Eitherway, I find the Sunni version to be a more logical account, Personally I would not be a Muslim if Islam was based on a chosen bloodline (Dynasty), like the Shias would have you believe.