The bag I got has this nice frame that pushes the bag out from your back, so you don't trap heat (and sweat) on your back. I can't wait to try it out in the heat this summer.
There is something really fun about running places. I mean, we log miles and miles and miles, literally running in circles, but seldom do runners run to get somewhere. I walk places, bike places, drive places, but never run. I think every runner should invest in a little pack to take with them, and try running (pun intended) an errand once or twice.
It really gives a different perspective on the sport.