Perhaps a Chromebook would work great for a Javascript or Dart developer, but what about C++, Java, or Android? Or even Go? I'm curious how well Google dogfooding Chromebooks would work out.
If you have to be on a laptop, the screens on the new Macbook Pros are simply a joy to use - as long as you aren't mucking with bitmaps too much, the clarity of web and code is really unmatched, eyestrain is greatly reduced.
Within the above restrictions (laptop, must be a locked/stripped-down OS), the Chromebook Pixel begins to make a lot more sense as an attractive laptop option.
When I do have to work directly on the laptop, I find it much less comfortable and slower. This is due to both screen real-estate and ergonomics. Your mileage may vary.
At the moment I'm primarily doing iOS and Java development (for a GWT web app), so I'm dealing with Eclipse, XCode, the iOS simulator, and a few browser windows. The secondary screen tends to be where I park reference material, IM, and sometimes logs. Eclipse likes to have a lot of pixels, but is a necessary evil to make Java development bearable.
How does Google deal with Java IDE's? Remote desktop?