I too have been working with 2 monitors for a few years now.
Track view on the left, Console on the right.
I wish I could add a 3rd for plug-ins and whatnot.

I also agree with John that dual monitors are also extremely handy even for basic everyday puting.
Moving files, having 2 or more web pages up for reference purposes, watching videos and pausing so you can try what you just watched etc.

I could never go back. I feel claustrophobic when I use my girlfriends PC. Always clicking, flipping, re-sizing and moving. UGGHHHH! lol  

Mike

It may not be essential, but having duals is sure nice.
I like having the main Sonar screen on one, and my VSTs on the other.
It's not unusual here to have Sonar open on one, and Photoshop on the other when building posts with screenshots.
I spend a lot of time working with new users, and to that end, it's quite useful.
Viewing a tutorial video on one, and having Sonar or whatever program on the other is very cool.
I've grown so accustomed to having different stuff on both monitors, that I feel really crowded on just one.
I've had dual CRTs for a long time, and only recently upgraded one of them to a flatscreen.
The room is a lot cooler now

Dual monitors enhance every aspect of computing for me. Sometimes you have to have two browsers open. Anything artistic like Photoshop or Illustrator is much better with two screens. Learning a new program is so much easier when you can have the tutorial on the other screen. When I do my payroll at the weekend, I have Excel, Quickbooks and Outlook open at once. I can split one screen into Excel/Quickbooks (Windows key + left or right) and have Outlook on the other screen. Before I had 2 screens, switching between apps on one screen felt like a real kerfuffle. 

Yup....been running two 28" Hanns-G monitors for a couple of years now....absolutely love it...!

I use a 28" Hanns-G for tracking, and this is flanked by 2 X 24" LGs: the left for console view (full screen) and the right for instruments and FX. Multiple monitors is definitely the way to go. Having everything open and in view really streamlines workflow. 
 

KEv

I know I'll be dating myself somewhat but reading of all the multi-tasking that leads to the real need for multiple monitors is making me long for the old school ambience of a single amber tinted monitor on a desk connected to a Wang Labs mini computer.  Just sitting quietly single tasking on lines of code. 

Nowadays at work I have Oracle in one monitor, Excel and a project controls database in another monitor, Lotus Notes and Communicator popping up when I get pinged, the phone ringing, my cell phone buzzing with texts and calls and, worst of all, people walking in asking "got a sec?"

As Firesign Theater says "Welcome to The Future"

I've been multi monitoring for years, currently running three. I found them almost a necessity with 8.5 and earlier versions. Since X1 they've been a nice luxury but I don't miss them that much when on my laptop. The new interface helps a lot in that respect.

Yep, love my dual 22" widescreen setup. What I have on each screen changes with screen sets. Gotta love screen sets!! lol  I don't find it distracting at all. In fact quite the opposite. Makes my workflow SO much faster and smoother.

I also have a laptop in the studio for video tutorials, internet surfing, up and downloading files, etc, as I don't have my DAW hooked to the 'net. So, I guess I really have THREE screens! HA!!  

Well, on the strength of this thread, I tried dual monitors for the first time this morning. Truth is, I erroneously believed my vid card couldn't cope. Apart from obstructing one of the sets of speakers, I am an enthusiastic convert. Cheers, Zen!

...dual monitors are very useful even if you are not running Sonar. The one thing they will do is make you more productive. And no they are not just a nice addition they make all computing better and faster.

I agree 100%.  My first experience of a dual-monitor setup was at work.  At first I couldn't see the point of it, but after a couple of hours I was hooked.  Going back to one monitor, you realise how much time you waste maximizing and minimizing windows.  After all, if you are trying to cross-reference information between two hard-copy documents, you put them both side by side rather than closing one before opening the other.  Why should electronic info be different?  The idea of a paperless office was never practical until multi-screen setups became affordable.