I have yet to attend a con myself, but i herd this one is popular. China Joy. its a game and anime con that will happen this summer! I hope to go!
here is another link to some of the photos from the con.
also if you are a cosplayer i have a friend who needs cosplayers for a book he is publishing! he needs lolitas, cosplayers, punks ect! leme know and i can give you his info !
i already had my shoot, and he needs more people!