I'm a huge fan of the emote. It saves a lot of time and adds a lot of flair to the game. The perfect emote at the right time can translate into real morale letting your ally or team know that they came through... that and the fact it probably saves a lot of bming that otherwise may go on allchat because a little popped up expression says it all.
So why, why, why, why Riot are we limited to only 6 of them? Just make it unlimited. They are really that great.