I hope you didn't have your heart set on that sexy 64GB SSD that Steve teased as an "option" during his keynote: the 1.8GHz version with the SSD drive standard costs a whopping $3,100. For comparison's sake, adding a 64GB SSD to a Dell laptop with a 128GB SATA drive standard is a $1,000 option. At Alienware, you'll pay $900 to upgrade to a 64GB SSD from a 320GB 5400RPM drive. Those are probably 2.5-inch SSDs, however.

The 1.8-inch SSDs used in the Macbook Air are pricier, with prices looking to be around $1,300 on their own around the web.

Source- http://gizmodo.com/345101/adding-a-64gb-ssd-to-the-macbook-air-1300-extra-please