Two monitors are better than one -- unless you have one monitor that's nearly the width of two. That's better still.
And that's the AOC Q2963PM in a nutshell. It's a 29-inch ultrawide display with a 21:9 aspect ratio. Normally it sells for $499.99, but for a limited time, TigerDirect has the AOC Q2963PM for $399.99 shipped. (It's also available at Newegg for the same price.)
This panoramic monitor employs in-plane switching (IPS) to provide a wide viewing angle, fast response times, and excellent color reproduction. It features DisplayPort, HDMI, DVI, and VGA inputs and both picture-in-picture and picture-by-picture capabilities. In theory, that would allow you to view, say, a Blu-ray movie on one side of the screen and a browser window on the other.
The screen runs at 2,560x1,080 pixels, which might be a problem for some graphics cards. You'll definitely want to check with your system manufacturer (and/or video-card maker) to make sure it can handle such an unusual resolution. Thankfully, AOC does provide a driver that should at least enable support for that resolution.
If you do want to use the monitor with a Blu-ray player, game console, or even an Android-powered device (an integrated MHL port makes it possible), you'll be glad to know it has built-in 3-watt speakers -- weak for movie or game audio, but better than nothing.
CNET hasn't reviewed the Q2963PM, but most of the user reviews at Amazon (where it's also $399.99), Best Buy (again, $399.99, but with sales tax added), and Newegg are of the four-star variety. Save for the occasional unit with some dead pixels, users seem to really love this thing -- especially for games.
Although $399.99 is still on the steep side for a monitor, keep in mind this is a 29-incher, one that usually sells for $100 more. If you want a lot of extra display area without the hassles of a second display, this is definitely worth a look.