Best Biking Backpack

Cyclists (road bikes): What is the best backpack medium lift, ie the change of clothes + sneakers?
Be Ergon is a murderer, but that kills $ 150.00. My normal backpack changes all over the place ..
I prefer not to carry anything on me except a little snack in the pocket of my shirt. I do not like riding with a backpack ever. Even the use of a camel back hydration system. If you have to bring what you show, buy a shelf and ride a bicycle trunk bag. Velcro is attached and can be easily removed and taken with you. Most are also extendable to an extra 3 inches height. In the regular size of a standard pack of 6 cans will easily fit an ice pack. Stay as if driving does not bother swinging motion.
How to Pick Bicycle Parts & Accessories : Bicycle Racks & Bags Tips