I'm with MacsAttack and Cloudane on this. I'd probably get a MacBook Air if 1) I had an iMac/Mac Pro to supplement it, 2) I had the money, and 3) my MacBook hasn't even had its 1 year birthday yet. Otherwise, I think it's a perfectly reasonable tool.
Honestly, I don't use most of the accessories most people here seem to think of as "necessary." And I even tend to think of myself as having greater computing needs than "average." But hell, I don't even know what 3G is or what I would do with an ExpressCard or whatever those things are. You guys are making me feel really out-of-the-loop.
What I do know is...
-Only four of the applications on my MacBook have required CD's to install: VMWare Fusion, Windows XP, SAS Statistical software, and XCode. The rest I downloaded as free, open-source software.
-I've never used my optical drive away from home. I haven't once. I rip music and movies at home and take them with me.
-I've never had more than one thing plugged into my USB drive at once, and then it's usually a flash drive, printer, or my iPod.
-I've never used my firewire, line in, or video ports at all.
-I've used my ethernet once. Once. And it wasn't even necessary.
-I don't need a small footprint; I carry a briefcase for my schoolwork and notebooks, etc.
-A thinner laptop gives me more room for schoolwork in there. 2lbs make not sound like much, but it's the difference between laptop alone vs. laptop + textbook I may need. Trust me, I'm in shape, but it still makes a difference when you're carrying them several miles to and from campus.
-I've never even touched my battery. My MacBook usually lasts me through the whole day, and if I really, really need there's usually outlets in at least one of my classrooms which can give me 50 min of charging. So much for needing extra batteries?
Wait, what?
But you're telling me the MacBook Air is inherently flawed? You're telling me if I bought one, it'd just be to be a trend-whore and turn heads, not because of any of the legitimate reasons above? Oh. Well. Nevermind, then.
If my MacBook needed replacing and I had the money, I'd go for the MacBook Air. Yes, it's expensive, but that's not a flaw of it; that's me being a poor college student. I'd have an iPhone, too, if I had the money, but most here agree the iPhone isn't an "inherently flawed" Apple product destined for failure. If my MacBook is getting old when MBA 2.0 comes around, I think I'll be in line for one. Right now, I'm just not in the market for any computer.