Why was Boromir allowed to join the Fellowship of the Ring after the Council of Elrond, where he succumbed to the Ring **moments** after first seeing it, and explicitly saying that he wanted to use it himself?  It was made absolutely clear that he could not be trusted around the Ring, but no one spoke up to say "Maybe the guy who succumbed to the Ring within seconds shouldn't go on the mission to destroy said Ring".  

Assuming that it was deemed necessary for the Fellowship to include a representative of Gondor (although Rohan didn't get a place in the Fellowship, for some reason), couldn't Aragorn fill that spot?  If not, wouldn't it have been worth the delay to send Boromir back to Gondor and request that Faramir (who later proved himself to be less susceptible to the Ring) take Boromir's place?  Granted, the Council had no way of knowing ahead of time that Faramir was stronger than Boromir, but it seems like Boromir was the **worst** possible choice, and anyone who wasn't Boromir would have been a better candidate.