I think the Dell Inspiron Mini 9 looks pretty cool. A 9-inch screen, 2.28 lbs, built-in WiFi, and (unlike the MacBook Air), built-in ethernet and two USB ports. $349 gets you a version with Mini OS (Dell’s version of Ubuntu Linux), 512 MB memory, and a 4 GB solid-state drive. Upgrade to 1 GB of memory, a 16 GB SSD and add a webcam and Bluetooth and you’re still under $500. Sweet!