Editors' note: As of June 2009, the product reviewed here has been replaced by these updated models.
The MacBook Air started the unibody trend earlier this year, and, thus, it doesn't receive much of an upgrade. Physically, it's the same as the original Air, but Apple squeezes a mini DisplayPort connection under the flap that hides the lone USB port and headphone jack.

As with the MacBook and MacBook Pro refreshes, the new MacBook Air ditches the Intel chipset for Nvidia and features integrated GeForce 9400M graphics. It also increases the front-side bus from 800MHz to 1066MHz, while keeping the Core 2 Duo processor offerings roughly the same, though the chips' L2 cache increases from 4MB to 6MB. The default memory is 2GB and you still can't upgrade beyond that, but it's now of the DDR3 variety. A 120GB (4200rpm) hard drive replaces the old 80GB unit, and a 128GB solid-state drive replaces the previous 64GB SSD offering.
The price of the lower-end Air remains $1,799, while Apple knocked $99 off the higher-end model, bringing it to down to a still pricey $2,499. That equates to about, oh, six Netbooks.
For complete coverage of the Apple notebook news, see "Apple polishes up its MacBook line."