What are important items for a touring first-aid kit? When riding long distances, either solo or with groups of people, it is obviously necessary to carry a first-aid kit in case of a crash or other injury. What are the most important items to pack, while still considering weight or space? What items can be included in 'travel-size', and which items should be 'full-size'? What items should definitely be left at home?
I bring enough to dress small cuts and stop bleeding, at least until 911 could get to me. If you're riding in areas you might not be able to be reached by emergency services, or if you have particular medical issues that need specialty supplies, a kit like this would insufficient. 


Bandages/band-aids of a few different sizes
Gauze -- usually a small roll
Tape -- small roll, enough to tape a skinned knee and a little more
Small tube of antibacterial gel (like neosporin) See GaryW's comment, below, liquid may (or may not) be more appropriate
Advil -- I usually have this in my handebar bag anyway
Alcohol wipes -- one or two individually-wrapped


Other things you might consider are snappable heat packs, a knee brace, and something to put on bug bites or poison ivy for rides in the woods. If you're allergic to bee stings, you might bring something for that.