Me and my friends are going this year. Went last year, stayed at the downtown Marriott.
On Day 0, you have to walk your way to and from the hotel. Walking around downtown LA by yourself is not advisable, if you have at least 2 people you'll be fine.
On cameras: by all means bring your camera and have fun. But at the big big events in Club Nokia and Nokia live, they will deny your entry if you bring your camera and use metal detectors to enforce it. So make sure you don't bring it then.
On lines: Day 0 pre-reg line is....insane. We flew in last year and arrived in LA around 8:30 am, got our SuperShuttle ride to the hotel (DO NOT USE CABS! THEY WILL RIP YOU OFF! USE SUPER SHUTTLE!!!). Checked into the hotel, went straight to the convention center around 9am and found a huge line already started. At least 100 people. So we decided to get in line and wait it out. That line grew easily to 2000 by the time they opened reg at 3:00pm, and they closed reg early enough that those at the end of the line had to wait till the next day. So for Day 0 wait: get there early, bring something to keep yourself busy in line, make friends with the folks next to you. I found AX folks to be very nice.
On money: unless you've been to any other Con besides NDK, nothing I can say will prepare you for the size and awesomeness that is the AX dealer room. You could easily spend your entire life savings there and still not have enough. Good news is, lots of industry folks show up, and give out tons of free stuff, so always be on the lookout for that stuff. Bring enough for food. You will be forced to eat out constantly. The con center has built in food, but its pretty freaking expensive. I settled often for the $8 cheap chinese food carts and drowned it in siracha sauce to make it edible.
Now to hijack this thread: Who all is going to AX? 4 of us here!