I have a wide screen monitor and have not had problems with any games refusing to display on it.
That said, occasionally I have had to enable auto-adjust on the monitor if the game doesn't center properly. (That's happened twice, and everything worked fine after the auto-adjust.)
There is also a subtle distortion on the wide screen monitor for certain games. 3D games and games with 360 degree panning look significantly better on the wide screen monitor than on my older monitor. However, for 2D and 2.5D games, like Martin Mystere and the Nancy Drew games, on my wide screen monitor, backgrounds look a bit more blurry, and characters all look like they've gained 30 pounds and have the jaggies.
You might want to check out an earlier discussion about this here.