hehe you seem to know all about it, but I'm going with a couple of friends to check out Long beach and the convention not really to explore the wonders of 10000 otaku not showering for 4 days.
This year there are gonna be some big name concerts namely the US premier of SKIN consisting of Gackt, Yoshiki, Miyavi, and Sugizo. Visual Kei isnt really my thing but those guys are kind of a big deal.

Anna Tsuchiya who sang the opening for NANA is also having a concert. SOS invasion tour with Hirano Aya and the other voice actors for yuki and mikuru from Suzumiya Haruhi are having a concert and panel. Chiaki Ishikawa, Halko Momoi, and ORESKABAND are also gonna be there, I dont really care about them but they are having concerts too. There is AX Idol, which is a Singing and voice acting contest and the Masquerade event. Those are the big events scheduled.
Theres all sorts of other little things you could do, screenings of old episodes of dubbed anime or something. 35mm movies and all sorts of anime/manga/japanese panels. The video game room with occasional gaming contests. Cosplay events I dont really care for but there are those. Manga Library, stuff like that.
Dealers hall and artist gallery are also a main attraction, they sell anime stuff and imported merchandise from japan, original artwork, fanart, and the doujinshi porn of course. Theres the sponsors booths, guys from adv, bandai, tokyopop, and other big name companies that got their booths promoting their stuff.
Theres also a summer festival going on around there. You can go eat takoyaki or yakisoba or whatever and try goldfish scooping and other festival activities.
Not that big a deal if you have a job, if not, save up your allowance and lunch money if you want to see a real live geekfest, just follow the smell. Maybe you'll see me, I'm gonna be wearing a business suit in 100 degree weather with a buttload of cologne.