Jaw-dropping. This is probably the first time I’ve considered going desktop-only (or, at least, desktop-primary) in about ten years. I do love the mobility of my Air, but this display is perfect. It’s also really reasonably priced — just $2500 to start, though you probably don’t want the base model.
I wish the Thunderbolt Display could be updated to this resolution. But, as Marco Arment explained, it’s probably going to be a long wait. You can’t even use the new iMac in target display mode, functioning as a really expensive Thunderbolt Display. Maybe the solution is to add a graphics card to the display itself; I’d buy one in a heartbeat.