Accessories for MacBook Air: External USB SuperDrive
More additional gear to carry for the lightest laptop you can buy -- Apple's external SuperDrive DVD writer, with a USB 2.0 connector and all the capabilities of a normal laptop optical drive. It's a $99 slot-loading 8x SuperDrive, full specs:
DVD±R DL/DVD±RW/CD-RW (gesundheit!)
Writes DVD+R DL and DVD-R DL discs at up to 4x speed
Writes DVD-R and DVD+R discs at up to 8x speed
Writes DVD-RW discs at up to 6x speed and DVD+RW discs at up to 8x speed
Reads DVDs at up to 8x speed
Writes CD-R discs at up to 24x speed
Writes CD-RW discs at up to 16x speed
Reads CDs at up to 24x speed
It's USB-powered and, I'd expect, a legit boot disk source. While you won't need a DVD drive for installing software, it'll definitely be handy for watching movies (the ones you don't rent).