The new 11.6-inch and 13.3-inch MacBook Airs are not that groundbreaking on the processor front, though an internal revamp has yielded a much thinner design.
Processors: Inside are anything-but-cutting-edge Intel Core 2 Duo processors running at 1.4GHz and 1.86GHz. There are also options for 2.13GHz and 1.6GHz processors. After almost three years, Apple has elected to go with Intel processor designs that have been available for a couple of years. For reasons not yet entirely clear--but likely having to do with heat, cost, and the Nvidia graphics chipset--the new Airs do not use Intel's newest Core i series processors, such as the power-efficient Core i7.
Graphics: The Airs have been upgraded with Nvidia GeForce 320M graphics--the same graphics now used in MacBook Pros. And that is probably the single biggest logic chip departure from the original MacBook Air, which used older Nvida 9400M-based graphics.
Flash: This is what Apple CEO Steve Jobs focused on the most and is in keeping with his MacBook Air theme of "what if a MacBook met an iPad." Like the iPad, there is no hard disk drive per se. "We've gone to complete flash storage," Jobs said. What this means is that the flash memory is built right on the system board and is not in a larger solid-state drive enclosure, creating more space for the battery and other components.
Memory: The Air can now be configured with up to 4GB of memory, exceeding the 2GB limit on the original. But this will add $100 to the price.
Battery: "We're moving toward some more stringent tests that get us much closer to real-world results. Even using these more stringent tests, we're getting seven hours of wireless Web battery life. The previous MacBook Air, using the old, more liberal tests got only five (hours)," Jobs said.
Screen and connectors: The 13.3-inch model uses a high-resolution 1440-by-900 (native) display, higher than the original Air. The 11.6-inch model has a 1366-by-768 resolution screen. The 13.3-inch Air finally has an SD card slot--but not the 11.6 inch model. There are two USB 2.0 connectors and a Mini DisplayPort.
No internal 3G: Yes, Apple stuck with Wi-Fi on the new Airs. In this respect, the MacBook has not met the iPad 3G (yet).
Updated at 1:40 p.m. PDT: adding screen, connectors, and 3G discussions.