QUOTE(NY-LON @ Jan 16 2008, 04:56 PM)

It\'s impossible to have an optical drive and a superthin subnotebook.

Notice that all of the other subnotebooks have optical drives. (Not that I think it's a dealbreaker, but just pointing out). My personal favorite, the Lenovo X60, is not on this list.
I'm not particularly impressed with the MB air specs. The hard drive runs at 4200 rpm, which is pathetically slow, unless you shell out $1300 extra for the SSD. The lack of a swappable battery means there's no way to buy a spare battery to double up for a long trip. For me, 2GB of memory is a dealbreaker - all of the other models allow you to upgrade beyond that. The stupidity of adding only one USB port astounds me, especially considering there is no ethernet jack or audio line in and
everything has to go through that port. You might as well include the ethernet dongle (and perhaps a usb hub!) in the weight of the MB air, since you'll need to always have it handy - there are still plenty of places where a wired connection will trump wireless. There's no expansion - no expresscard or anything - so if, for example, you want wireless broadband that's going to have to go through the USB card too. There's only integrated graphics (common on notebooks, but the comparable Vaio actually has a discreet nvidia board).
It's a slim machine, but some of the tradeoffs they made just aren't worth it. I'm a huge fan of tiny laptops - my next machine will likely be a Lenovo X60 or one of the tiny Sony Vaios - and I understand that you have to accept a smaller keyboard and screen, a bit less power, and a higher price for the convenience. But the MB air's lack of ports makes me think it will just be a pain to use.