I do most of my work on my laptop (13" 2011 Macbook air) and make heavy use of keyboard shortcuts to control my digital workspace, to replace the need for extra monitors.
I often have my iPad mini beside me, either for reference or entertainment - and sometimes I will use it with a bluetooth keyboard if I'm going to be doing a lot of typing (like using SSH or taking notes)
I have accessories around that I use sometimes:
But in general I can pack up my 'office' and take it to a café or anywhere I go when I'm travelling, it's a pretty simple and self-contained setup :D