FYI...there are other brands that fall under the "ultra portable" label as well. Technically, they're aren't as light or thin, but they do come with optical drives and are cheaper as well as offer more storage and better CPU speeds. In the end, ask yourself, is saving 4 ounces and an 1/8 of an inch really worth 3-400 bucks to you?
Don't listen to Charles, he and Steve Jobs went through a bad breakup a few months back and he's still bitter.
and the Air is only worth it if you're going to take it around with you basically every day, imo. i take my 15", 5.4 pound MacBook Pro with me to school every day and don't think twice about it. it's not much larger than a regular 3-subject paper notebook. I can't exactly put it in my purse, but I'm ok with that. it cost a little bit more than the air, but it's an awesome computer.