For superior screen resolution, it's hard to top the pixel-packing displays of today's tablets. The 3rd-generation iPad, of course, features the dazzling 2048- by 1536-pixel Retina display, and court documents from the Apple-Samsung dustup show that Samsung is developing an 11.8-inch tablet with 2560-by-1600 resolution.
Most ultrabooks are stuck at 1366-by-768 pixels, but that's changing. Toshiba's Satellite U845W models have 14.4-inch displays with 1792-by-768 resolution. Lenovo's ThinkPad X1 Carbon is 1600-by-900, and Acer's Aspire S7 is 1920-by-1080. So ultrabooks are catching up, but tablets still have the resolution edge.