I do use Revolution on Dixie 8-9 months out of the year.  I like to give her a "break" from the chemicals during the winter months.  She is microchipped and I use the Home Again service. She has that tag, along with a tag from the AKC (for a small one time fee they provide an 800 number and will try to contact me), and her Vet provided tag.  I have been intending to get another tag made with my cell phone on it, but keep forgetting.  Also a good idea about the vaccination papers.  Like you, no one has ever asked, but copies would be easy enough to make and tuck in the glove box.  Again, thanks!

I tend to have most of the bandage material also in case  of wounds on ourselves and often am more likely to use the antiseptics on us.

Heres a link to the aspca pet first aid kit---you can probably modify to suit your needs.  It is also a good idea to have poison control hotline number available.  http://www.aspcaonlinestore.com/index.php?productID=1930

We have emergency heat camp blankets that we got at a camping store for our backpacks.

I have several sizes of syringes.  I have to admit that the first time I took the dog to the beach, I brought antibiotics and sedation drugs in case I had to suture her up.  I am less paranoid now. 

 

Also, most importantly, good identification tags on collar with current phone numbers--cell phones if no one would be home to answer phone.    Microchips can also be help as long as the contact information is current.   May need to carry current rabies vaccination certificate as many parks will say they require it but I have never had one ask for it. 

 

I am sure there is more that I am not thinking of.  My first aid kit weighs a ton and is only good for car/trailer travel. Not a hiking kit itself.  I have it all in a tupperware container but any water tight container would work.  Gel ice packs are a good idea -- I just keep forgetting to get one.

What do you think a good pet first aid kit should contain?