Monitors: 2x24" IPS dells vertical, with 30" dell IPS horizontal in center.
And of course a Das Keyboard for the hands and a HM Aeron rescued for $175 from a dead '99 internet startup!
I found this setup to be perfect for two-up windows of code plus email/browser for reference, plus output of what im doing.
Most of time is spent in python/web. Also lots of manual (excel) data analysis, visual studio, and db-related things.
For travel, an old-ish 11" MBA, which I absolutely love.
Aside from the monitors, the setup is actually a lot cheaper than one might think - e.g. raided HHDs, video card, etc are all reused from old machines, 24" monitors are 7 and 4 years old, respectively, etc.