There is one item of note on the Dell widescreens (I own a 20" - 2007WFP).
In the onscreen menu, you will find the 'Display Settings', which have a nice feature that allows you to set one of the following when not in the default native resolution:
1:1 pixel ratio (meaning that if you select say 1024 x 768 pixel resolution, that is exactly what you will see - a 1024 x 768 image surrounded by black bars).
4:3 ration (using the same example of 1024 x 768 pixel resolution, you will see the image expanded to the full height of your monitor while keeping the aspect ratio intact - resulting in vertical black bars on each side of the image).
Fill - which is the setting used to fill the monitor screen with any image.
The nice thing about these options is that if you play an older game that does not support widescreen resolutions, you can set the display resolution to a size supported by the game, and then use the monitor's display settings to select either the '1:1' or '3:4' settings which will allow for the proper image during game play.
Note - the '1:1' and '3:4' options are greyed out when in the native resolution, so you need to change the resolution in Windows display properties\Settings tab before using the Dell monitor's onscreen menu to access and apply the optional ratio settings.
A nice touch by Dell - IMO.