Copy and paste from my post in another forum:
There are multiple widescreen resolutions:
16:9 ratio:
852x480
1280x720
1365x768
1600x900
1920x1080
16:10 ratio:
1280×800
1440x900
1680x1050
1920x1200
I like how Valve group these options by the ratio in their games' video settings, other games sometimes mix all those resolutions and confuse you when choosing. Wish more game developers will do the same/similar thing.
If you're playing older games that may not support widescreen, you should check this forums if there's a fix for them:
http://www.widescreengamingforum.com/forum/viewforum.php?f=32
Some monitors, like the 24" BenQ has a feature to enable 1 to 1 pixel mapping. Not all monitors support this though. I have a 22" Acer myself, and as far as I can remember, it doesn't have a 1-to-1 pixel mapping feature.
Widesreens are awesome for movies.