Singletracks.com has an interesting article about the Camelbak waist bag. The bag looks like a refreshing alternative if you don’t like to have a full backpack.
Yes, it takes some mental rehearsal to get rid of the sad fanny back reputation.
Anyway, it allows you to pack plenty of supplies for a your ride. I suppose we will see more and more hip bags on the market.
I think if you want to go even lighter you can use a small runner’s waist pack that has a pocket for a water bottle, and some room for your gear.
For shorter rides these kind of waist packs are probably a lot more comfortable than a full-on backpacks.
Bigger backpack is still needed for those more remote and longer rides.