I carry everything in a backpack. I do my grocery shopping at Costco in the truck so whatever I pick up at the store is usually last minute items or small things. I don't like panniers coz I didn't like the feeling of the bike's weight shifting everytime I came to a stop and leaned the bike to put my foot down. But I'm probably more the exception than the rule.
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"