Push through literally hundreds of gawking Macheads and you could actually touch a real live MacBook Air on the Macworld show floor today. (In lieu of anything else interesting announced today, 100 percent of the focus of Macworld attendees was squarely set on the Air.) I got a brief chance to check out the Air in the flesh. Some thoughts follow.

First and foremost, remember this is an ultralight laptop. That means tradeoffs. In this case (as is the situation with most ultralights), that means no optical drive. Some are already whining about this, but an optical drive is really only important for those who spend a lot of time watching movies on their computer. (Even then, Apple would probably direct you to an iTunes rental instead of a DVD.) Watch a lot of flicks? Don't buy this machine. Want the absolute lightest machine you can carry? You're solid. Don't worry about installing software; it's easy to share the drive on another computer when one is handy.

But wow, is this thing thin! Pictures don't do it justice. You have to see the thing in the flesh to believe how slim it is. Part of that is optical illusion due to the curved edges, but even at its thickest part, those of you used to the usual rectangular laptop slabs (even Macs) will be awestruck by its waifish look.

Other compromises are less thrilling. The single USB port is a terrible choice, if you ask me. Plugging in a thumbdrive will mean unplugging your printer, mouse, or external keyboard. No Ethernet port? Terrible idea. And that Micro-DVI port, which will require a custom adapter, will never be used by anyone. I like having the ports underneath the closing flap, but there really ought to be another set of ports on the other side of the machine. Another gripe: Here we have yet another Apple product with a sealed, non-user-replaceable battery. Argh.

Some good news: The screen is gorgeous and bright. Those LED backlights are the real deal. The keyboard (no miniaturized keys here) is also solid.

The 1.6GHz Core 2 Duo and 80GB hard drive are adequate. The 2GB of RAM is a nice addition; many vendors would have stripped it to 1GB just to save 20 bucks and one ounce of weight... which leads me to the price tag. At $1,700, you won't find many machines in this weight class on the market for such a low cost. (Yeah, I know many of you think $800 is too much to pay for a notebook, but in the ultraportable world, $2,500 and $3,000 prices aren't uncommon.)

My current favorite 13.3-inch notebook out there is the Dell XPS M1330, a 4.8-pound machine with an optical drive, 160GB hard drive, and 2GHz CPU. (You can bump these specs up or down.) Its price: $1,424 for a solid configuration. Not that much less than the Air, but considerably more full-featured.... though it's quite a bit heavier, with almost 60% more weight.

What's the value you put on heft? Is trimming an extra few pounds off your load worth the loss of an optical drive and connectors you take for granted? That's the question you'll have to answer for yourself, and while I think the Air is a killer entry into the world of ultralight laptops, I also think there's a (good) reason why most people opt for larger notebooks in the end.