As far as gaming goes, some race/flight sims properly support triple screen setups. Those games use multiview or multiprojection (as it's being called now). Race/flight sims with proper support allow you to input the distance from your eyes to the main monitor as well as it's width, they also allow you to specify the angle that you have your side monitors at in relation to the main monitor. The game will then take that information and create 3 separate cameras in game oriented where your head should be with the angles and information provided to create the most realistic view as it would be seen from the car if you were actually sitting inside it. Those 3 images are then composited into a single image and sent to your video card for display.
This fixes the stretching problem when you use super wide resolutions or ultrawide monitors (the stretching/fisheye effect is best seen when in a car cockpit and the side mirror takes up the whole left screen).
99% of games don't support triple screen properly and just support large/wide resolutions, nothing special has to be done to support that, they just have to allow it (which is why it's possible for old games to support newer, larger resolutions, the resolution option just has to be added most of the time).
I hate stretched/distorted images so I don't use triples for games that don't have real support for it.
As far as productivity, multiple monitors is far better then a single large monitor. Being able to maximize windows to the monitor they are on alone is great, fiddling around with window sizes on a large screen when you need 5 windows open sucks. Also, you can play games in fullscreen mode and still be able to view your peripheral monitors at the same time which is quite handy.
