Khal Drogo, from Game of Thrones:
Gaston, from Beauty and the Beast:
If I do Drogo, I'm going to have to learn at least a fair amount of Dothraki (the language they made for the show) as well as stop cutting my hair, as well as my beard. I'll also need to supplement my workouts with more pectoral-specific exercises.
Costume wise, I'm going to need to start early on Drogo. I need to make his Leather Girdle, Bracers, an Arakh, two knives, the horse belt, leather pants. skins/feathers that hang, beads (lots of beads) and figure out how to do hair-extensions well.
Gaston is relatively less intensive/expensive, being a shirt and some pants.
Both of them require me to get a nice pair of leather boots, though, which i can't complain about, and both require that I tan up a bit, (Drogo far more than Gaston) which may be a challenge as I'm paler than most people.
Drogo excites me as I'll need to learn a lot of stuff to do it, from cold-casting with resin, to leatherworking, to silicone molds. Drogo is furthermore a bit more topical than Gaston, given that the show Game of Thrones is very 'this year,' and Gaston is timeless. There's a multitude of arguments, one of which being Next year i'll have a lot more chest hair. The best two arguments for either are the following:
Ultimately though, I think that I'll be making a Drogo Costume regardless, as that might be something fun to wear at Otakon. So perhaps Otakon = Drogo, halloween = Gaston. Either way I'm planning on chronicling my progress on either here.