Mac OS X Lion which will be released Summer 2011.
Some notable features of the new operating system include: an app store (launching within 90 days on Snow Leopard), an application launchpad (kind of like the iPhone app icons), full-screen apps, improved gesture navigation, and Mission Control (improved window management interface combining Exposé, full-screen apps, dashboard, desktop, and dock).
iLife suite (version 11) was also announced for $49 featuring updates to iPhoto, iMovie, and GarageBand.
MacBook Air models featuring complete unibody aluminum construction, no optical drive, no hard drive, complete flash-based, solid state storage (up to 256GB) and FaceTime camera. The New MacBook Air is .68 inches at its thickest point, .11 inches at its thinnest point and weights 2.9 lbs (2.3 lbs for the 11.6" model). Prices start at $999. See full specs here.