I'd go diphenhydramine over other antihistamines, for an emergency kit. It has sedating properties for sleeping, anti-nausea properties, and of course for the emergencies, anti-allergic. For such multifunctional use you do generally need the antihistamine to be sedating. Diphenhydramine powder also has analgesis properties (similar to a local anesthetic.)

I like ibuprofen just because it works on me for muscle pain and headaches, more so than aspirin or tylenol. In an emergency situation, I think muscular pain relief is most important and ibuprofen seems to work well for most.

Eric