I think ibuprofen is a better choice than aspirin or Tylenol, if you only plan to carry a single pain reliever/anti-inflammatory. Aspirin is not a good choice if someone has a serious bleeding problem. And more people seem to have negative reactions to aspirin than other OTC pain relievers. Ibuprofen also seems to be a safer choice to use in higher than normal dosages than either aspirin or Tylenol.

Aspirin might be worth bringing on its own in case of heart attack.

Drugs you use on a regular basis are worth having in your kit just because you use them regularly and might need them.

20 Immodium tablets seems like a lot, but its not as if they take up that much room.

I don't use antacids, but do have some generic Pepto Bismal tablets.

JMO.