If you hike with your dog...and you should!!!...take a look at this doggie backpack.
http://www.rei.com/product/803423/re...dog-pack-small
I have several models and I use this one the most. It has become my favorite because it's easy to don & doff, has just enough room and features without being too heavy. It looks like they introduced new colors and have put the old colors on clearance at REI. It's available in S/M/L. My dog is 60lbs and wears a medium. Check it out.