I use a relatively large seat bag, a top tube bag and my jersey pockets to hold what I need. Usually, I plan my routes to pass by a convenience store or gas station for extra provisions. This past weekend, DH and I did a route that we weren't sure had a store along the way, so we brought our Cambelbaks. Ouch. While I find it to be relatively comfortable on my mountain bike (and it's more upright position), I found it hard to wear by the end of our 45-mile ride. My low back was killing me. My guess is that I could get used to it, but I don't think I really want to use it for most rides.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher