AB was my first and favorite con, too ^^
I'm definitely bringing GLaDOS back (there are a bunch of us putting together a Portal group with all the cores). I also am hoping to have Princess Cadance from My Little Pony done in time. Could possibly have a Shining Armor with me. And for Sunday I will probably bring fem!Canada from Hetalia.
I'm personally happy it's in March. Less time to wait for it to get here, and most of my cosplays are long-sleeved, so I prefer the cool weather ^^