I have three 25" monitors for web development, and every inch of each is used up by my work. I could probably fill another three with just a single site's development windows, instead of tab switching.
Sure. I'll load the rendered view of the site I'm working on and flip through tabs on that window. Typically this takes up a whole screen, and It'll resize frequently if I'm working on a responsive site.
Usually the code editor or IDE takes up a full screen, with it's file tree view or whatever even a full screen can be cramped.
The document inspector/developer tools almost dominate the other screen. If you're used to development in that tiny framed view below the browser, do yourself a favor and pull that sucker out; Get a real look at your rendered document and network profile while you're at it.
Any left over space trades between the terminal, gui file transfer, irc, music player (wait let's keep this work related ;), spec documents, email, code references, credentials manager, file management...
I really could load up three more screens just for a normal workflow. I can screenshot if there's interest.
Four screens for me. The left two 24" screens are connected to a Linux Mint box. That far left has a browser with developer tools. The next one has a full-screen vim session.
The right two are connected to a MBP. The left 24" has terminals (ssh'ed into the linux box) for Rails console, MySql and Rails log running in real time. The laptop's built-in screen is the far right, with everything from Assembla to email to Skype, etc.
Here's a typical screen-shot of how I work: http://i.imgur.com/UVOfAan.jpg
As others have said, I can also do with more screens. At the moment both the Linux box and the Mac has 3-4 virtual desktops each.
I have the same issue with space on a 3-monitor setup. I simultaneously use Chrome, the Chrome inspector, an editor, terminal, Skype, an IRC client, sometimes Firefox, Finder, etc. There's always more things you can put up if you have the space. If I had 6 screens I would dedicate one to a dash, but with 3 it's better used directly for development.
I have 3 monitors: a 23", a 27", and a 13" macbook air from left to right. I keep gmail open permanently on the 23", coding editor on the left half of the 27", coding output on the right half, and http://www.sublimedash.com on the macbook air.
I have three monitors. I mostly do backend development so I generally have one monitor dedicated to terminals, one to vim and one for browser windows, HipChat, mail, etc.
