When Apple held one of its big keynotes last week, it was easy to think of it as "iPad day." Sure enough, the company announced some upgraded tablets, but it was a desktop, of all things, that stole the show. Though the new 27-inch iMac with Retina display has the same overall design as Apple's previous all-in-ones, it ushers in a 14.7-million-pixel 5K display with screen resolution of 5,120 x 2,880. That's seven times as many pixels as 1080p, and 67 percent more than you'll find even on a 4K panel. I'm not exaggerating when I say there's nothing like it. As it is, you'd be hard-pressed to find a 4K all-in-one, and meanwhile, here's this machine from Apple, with enough pixels to view a 4K video at full resolution, and still have room left onscreen for other stuff, like the Final Cut Pro dashboard. Needless to say, it's in a league -- and price class -- of its own. Starting at $2,499, it's more expensive than almost any other all-in-one on the market, even the supposedly high-end ones. As it turns out, though, if it's this kind of screen quality you're after, this might well be your only choice.