Like Linus with his blanket, I started by carrying the MBA in a padded sleeve case inside my regular bag for the first two weeks. This almost eliminated the the two pound (give or take) advantage of carrying the 3 pound MBA over its larger cousins.
Any bag I carry ends up being a virtual tub for whatever I think that I may need with me. It's a catchall for every accessory, magazine, peripheral and other pointless item that I pick up in my travels. And the larger the bag, the more junk it attracts. All these extra items really add up and my bag ends up weighing the same (or more) than it did with a MacBook or MacBook Pro in it.
The tipping point came Friday when I gutted my bag and realized that there were a bunch of items in it that I hadn't needed or used all week. After filing away all of the paperwork and putting away the accessories, recycling all the magazines and newspapers I vowed to go sleeve only from now on.
It's a total lifestyle change and you have to force yourself to do it, but 90 percent of the time I only need my MacBook Air. What's the point of carrying a bunch of printed material that I already have on the MBA? Why carry paper notebooks and notepads when the MBA can do that too? Magazines? Newspapers? Bah. That's what RSS is for baby!
Granted, going on a business trip or vacation requires a larger bag with more accessories, but my daily commute requires next to nothing. I leave an AC power and video adapter at my office and I keep a JIC (Just In Case) accessory bag in my car that has an AC adapter, Ethernet dongle, USB hub and my USB hard drive. (I didn't need anything from the JIC bag all week.)
While it won't suit everyone, if your daily commute consists of going from home to office or school five days a week and you don't need an optical drive or massive hard drive then the MacBook Air in a simple sleeve case is a game changer. For me, the MBA is the ultimate blogging machine.
I suspect that many notebook computer users could function with a thin and light notebook computer and can't help but think that we've been brainwashed by the computer manufacturers into thinking that we need a bunch of extra stuff with us all the time.