anybody use dual monitors?

Always. For work (at work) and for play (at home).
1 is the main one, for the game I'm playing or thing I'm writing or page I'm actively browsing, one is the off-monitor for, well this forum right now, or youtube in background etc.

tempted to buy one so that I can play sims whilst having things open in different monitor screen

Indeed, for several years now... when at work (retired now) and also at home (I play a few online games :) )

I use 3 monitors on my desktop.

Do it, its very good, my sim is raking right now so I'm here on forums and on youtube :)

Just make sure they are somewhat similar in quality (aka if your current one is old and crummy the new one will be very different feeling).
also practically speaking, make sure both have same kind of lift/raising features (aka u cant raise at all or can lift monitor higher on its own stand) - i have to stack my 2nd monitor at work on boxes to make it match in height

Of course. Once you're used to it, it feels so bizarre to just have one.

Yes. One monitor is for chumps. ;)

As others have stated. I also use dual monitors. While I play the sims I can look over here and enjoy the forums~

One of my desktops uses dual monitors, the other doesn't because I don't have the space.

Yes; main one is a 32 inch HD TV and the secondary is a smaller 15 inch VGA monitor. I always play Sims in Windowed mode in case I want to do something on the side while it loads and dual monitors are especially useful while streaming games/other things.