Our enthusiasm for Speck's new PixelSkin HD Wrap for iPad 2 ($50) is directly related to that hard to quantify, "know it when we see it" factor that distinguishes big deal case designs from all the rest. By combining the best features of its excellent PixelSkin HD case for the iPhone 4 with the dual-purpose front lid and triangular stand found in the original iPad's CandyShell Wrap, Speck has come up with a really eye-catching, slick new folio design…