[jrockway]

I actually use a Chromebox: http://promos.asus.com/us/chrome-os/chromebox/

I have the i7 model at work and an i3 model at home. Both are fast. I also have a Chromebook Pixel for situations that require a laptop.

As for monitors, both the desktops and laptops handle my 4k monitor OK, but only at 30Hz (because it's a Displayport MST model which are horrible hacks and are thankfully no longer made). At work I use a 24" and 30" monitor. Works as expected.

You can tune the density per-monitor, so you can run your 4k monitor at 1.25x or 2x density and your normal monitor at 1x density and it Just Works.

It's a pretty nice OS.