Eh, I disagree. The cockiest clan ever would have to be [YES], due to the fact that they had the balls to make it. Apart from that, #h, or Colon-3, or one of those newfaeg clans with all the newer gms/staffers.
Maybe [One], or whatever
I personally don't mind eVo's "cockiness", for the majority of the members at least have the skills to back up a lot of the overweening statements they might say.
[RAWR] "Probably better than you"
Naw, I don't think it is them, but that is a pretty cocky clan description :3