Dell's UltraSharp displays still have a certain cachet among sticklers for quality, most of all at the high end -- so today's release of three advanced models might as well be a bonanza. The 24-inch U2413, 27-inch U2713H and 30-inch U3014 (above) once more center on PremierColor and the visual accuracy to match. Even the two smaller displays have a 12-bit processor that helps their LCDs reach 99 percent of the Adobe RGB color space and all of the sRGB space, or enough of the spectrum to eliminate most rude surprises with photo work. W