Vicemage
Plus, there's always those nasty-a** people who never wash after using the bathroom. (my kingdom for a "vomit" emote).
Hence the hand-sanitizer.
3nodding I use it right after I shake someone's hand, especially a cosplayers'. (Not because I think cosplayers are dirty or anything, but they tend to come into contact with a lot more people and thus have more of a reason to have germs on their hands.)
I've never gotten sick after a con, but I can see the use of things like Airborne. (I heard there's nothing that actually prevents you from getting sick in it, though. Just vitamins and stuff.)
List of the things mentioned so far:
-Hand Sanitizer
-Camera/Film
-Water
-Airborne
-Advil
-Food Money