I will presume you're looking at a 9300, where you can get either 17" display type.
The base (standard) display is WXGA+, has a non-glare screen, and native resolution is 1440x900. $125 buys you a TrueLife (bright) screen WUXGA with native resolution at a very high 1920x1200. My XPS m170 has the second (bright) display. While it's nice to see more of everything on screen, the text size is tiny. You can tinker with XP and get larger type size (that's what I did) that will help. Unless you have very good reading vision, reading the text online will be trying. I simply use my reading glasses when needed!
If you plan on playing games, I strongly recommend you NOT settle for the X300 graphics and splurge on the 6800 Go with the base display. You should be able to run games at the native resolution very well. But at 1920x1200 the 6800Go will choke with details turned up. My 6800 Go Ultra strains some at max resolution in a few games. You could always run at a lower res, but you will get degraded image quality.
HOWEVER, playing DVDs on the bright display are simply stunning. The bright display allows you to see colors as they were intended. This is also a BIG plus while playing games.
The downdside to the bright screen is reflections - unless you are in an IDEAL situation you WILL see glare! It doesn't bother me much, but to each their own.