But in service of slimness, something had to go, and depending on how you use computers, these compromises might either be negligible or deal killers. To maintain its Zen-like profile, the Air has a minimal selection of ports--one USB, one for video output to a bigger screen, and a single jack for earphones. That's it. Many people will choose to pay $29 for a "dongle" that plugs into the USB port to allow the Air to be plugged into Ethernet. There's no slot to plug an EVDO card for cellular broadband, so if you want that, you must use a different USB dongle connecting to a card for that purpose. No Firewire port either. Since so many things may vie for the single USB port, it might be wise to buy a hub that multiplies a single USB socket to many, even at the risk of spoiling the Air's sleek figure.

Another red flag for some is that, like the iPod, the Air has a fixed battery that users can't replace. Apple says that all but the heaviest users won't need a replacement for years, and that when you do need one, Apple will instantly replace the battery at its retail stores for $129.

There's also no built-in optical drive (that's the component that reads and writes CDs and DVDs). Apple downplays this omission partly by saying that in many ways the optical drive is obsolete (why watch DVDs when you can now rent movies with iTunes? Good one, Steve.) But its main compensation is a new feature called Remote Disc. This allows you to borrow the optical drive of a different computer so you can play homemade DVDs, install software, and, most importantly, use a boot disk to revive a damanged operating system. Clever idea, but trickier than it sounds--for instance, it only works on Macs or Windows PCs equipped with fairly recent operating systems. It also took me a session with Apple technicians to deliver this important hint to you: when using Remote Disc (and the Migration Assistant program that lets you wirelessly move your previous computer's files to your MacBook Air), set your firewall at the lowest security level. In any case, those solutions aren't as effective as what they're replacing, and MacBook Air owners would be nuts if they didn't buy Apple's new external disk drive, the $99 Superdrive. (Of course, that's one more suitor for that lone USB port.)

More disturbingly to power users, the maximum built-in storage option--the only one--is an 80-gigabyte hard drive. Apple insists that if it used the 160-gig hard disk drive it offers in its high-end iPod classic, it would blow the profile of the MacBook Air. Eighty gigs isn't much these days; you can get a bigger drive on even Apple's low-end MacBook. In one sense, this is a prescient look forward to the day when people will store their all-digital assets remotely, "in the cloud" as this concept is called. But since it's still a couple of years before my voluminous iTunes collection of movies and songs will be stashed in the ether, I need a computer with a standard-size drive, and the MacBook Air will work for me only as a second machine, a luxury item for on-the-go use.

These omissions are troubling--especially to someone in a down-turning economy deciding whether to spend a premium sum for a computer with subpremium storage. Still, simply using the MacBook Air, as I'm doing right now in writing this review, is rather copacetic. Though I can quibble with a few of Apple's choices of what to take off, the product's dimensions and design make the case that the losses were not in vain. The things that Apple left on were the ingredients for a quality computer. And did I mention how thin it is?

© 2008