I use a Macbook Pro with the screen extended to an iPad Mini via Duet and usually need nothing more, but when I do need more management I use the workspaces feature built into OSX. It's a perfect balance of portability and productivity (most of my work has been remote, lately - so I don't sit at an office). If I need to get a broader look at a lot of data (say, on a dashboard), I airplay directly to my smart TV.