At the WWDC 2012 conference held by Apple a number of new updates were announced. If interested you can watch the Keynote Presentation here.
Both the new Macbook Pros and the Macbook Airs have been upgraded with Ivy Bridge processors, USB 3, and at a minimum Intel HD 4000 graphics. This is a pretty significant upgrade as graphic performance should see a considerable improvement and USB 3 is extremely fast compared to the old USB 2 we have been living with for years.
The high end Macbook Pro also has a redesigned (thinner) case and a “retina” display that contains 220 pixel-per-inch with a resolution of 2880 x 1800.