very true. i pointed out in the slate thread the guy was complaining about the difficulty of bringing a big bag of dog food home.
that would be tough even with great panniers. i'd buy two smaller bags, and when i shop i make more frequent trips to the store on the way home. i shop online. i'll never be able to fill up with a drum full of peanut butter at costco with a bike.
when you save money utilizing bike you also incur small expenses in other ways: better outdoor clothing, eating a bit more, buying at a small hardware store instead of home depot, but you shouldn't complain about those small inconveniences or expenses with the major financial and health benefits of bike. at the end of the day you're still way ahead.