Answer: ALL of them.
That is, all of them if the geeks in question are geeked about anime/manga and the hall in question is a cavernous corner of the Anaheim Convention Center. Organizers of Anime Expo 2006 announced today that their largest-ever exhibit hall–which will be filled with its most-ever vendors–has already sold out its July 1-4 run. What's billed as North America's largest anime/manga convention will be marking its 15th consecutive year at the convention mecca across the street from Ricky Rat's place.
We still recall the time, years ago, when we pulled into the Anaheim Convention Center for a ski show and had a difficult time finding it amid of a sea of costumed Star Trek conventioneers. Of course, if fights had broken out in our respective lines, it would have been no contest, because we were packing pointy ski poles and they were packing phasers that would not go to stun no matter how hard their bony little fingers pressed the buttons. But a battle royale between Star Trek geeks and anime/manga geeks: now that would be worth the price of admission right there.