Try an emergency maneuver when your shoulders are restricted 'cause you needed to tighten your straps 'cause you happened to stop by the store and added a little weight to your pack and now it feels like you've got a bowling ball swinging around between your shoulder blades.

Some riders - and you know who you are - go on about how panniers or trunks are dorky, and how you'll only carry so much in your bag. I think it's more about style than substance. But when push comes to shove you need a system that can adapt to a variety of situations - be it a commute or extended day trip. I have both a trunk and a set of panniers. The trunk works great for commuting to work. But just the other day I needed to pack a lunch, extra layer of clothes and a camera (a good size one). That meant double panniers.

If you can't afford both a trunk and panniers get the latter. If your load is light there's no law says you can't mount just one side. If you're bound and determined to try carrying your load on your back (yea, it's kind of cool to just roll up, hop off yer horse and stroll inside without having to fiddle with your geeky bike luggage) try a proper messenger bag. They're not cheap, but they're designed to be a lot more comfortable than a pack. Back packs are only good for sore armpits and sweaty backs.

DanO