camera, mexico is not what american media makes it... i live in mexico city and i feel just as safe as when I lived in Chicago...
You should bring whatever you want to bring!
Armored trucks, shotguns, AR-15s, frag grenades, RPGs, and your own private army to go with it. Where do you get all this equipment, you ask?
Why the ATF, of course!
Bring a camera because there's usually so many fun things to shoot. If you are in a city take some candid shots of people. I like getting a disposable underwater camera for snorkeling, too. What part of Mexico are you visiting?