Separate keyboard (a Kinesis) on legs slightly bent. I'll prop up the laptop keyboard (like right now) for brief typing, but I agree that'd suck for serious work.

I am not an ergonomics authority.

I use Vim, both for writing code and as a chrome plugin, so I'm usually just hitting a few keys in normal mode, or whatever autocomplete tells me, with the occasional swipe at the trackpad. I've never had any wrist pain on the couch. My macbook air is pretty ancient but it's still super light so I can just prop it wherever.