Most popular female character costume seemed to be Rikku (FFX, FFX-2), edging slightly ahead of Yuna (FFX, FFX-2), who was in turn just ahead of Rinoa (FF8). The most popular male costume was Vash, by far.
I got a chance to play Pop'n Music, and was impressed. linmayu and I got to watch the Anime Music Video set "Too hot for ACen". We were carded to enter the room, where we saw videos ranging from the fairly innocuous Pokemon video with "All the bitches love me 'cause they know that I can rock", to music set to hentai.
I'm more inclined to watch bizarre things at a con. I'm not likely to buy hentai or yaoi, nor do I have good leads for borrowing such material. A con's a perfect place to see things I wouldn't otherwise be exposed to.
We're almost certainly going next year, and will try to survive on less sleep, and get the hang of things earlier.