Hard to believe it's only been 10 months since the last iMac update, but Apple's venerable desktop needed a quick bump to stay current with Intel's Sandy Bridge processors and the Thunderbolt interconnect. So here we are, looking at the $1,999 27-inch 3.1GHz Core i5 iMac, which is the fastest stock configuration. (There's a 3.4GHz Core i7 available build-to-order, but we wanted what you could buy in a store today.) In addition to the new processor and Thunderbolt, Apple also bumped the graphics card to an ATI Radeon HD 6970M, which the company claims offers three times the performance of the outgoing model, added a 720p FaceTime HD webcam, and tucked an ambient light sensor into the case for automatic brightness adjustments. So has the best all-in-one PC gotten even better, or is Apple just keeping pace? Read on to find out.