:welcome
Here's how you can find info on a specific game:
-from the navigation bar at the top of the page, select
Games, Hacks & Tools
-from the drop-down menu, go to
Master Games List
-from there select letter C and look for Counter-Strike (version 1.6).
CS 1.6 supports widescreen natively, so you should be able to play at your monitor's native resolution (1440x900) no problem. Which is "the best way".
As specified in the Detailed Report:
Just go to the video options menu, enable widescreen from the drop-down menu, and then the list of available resolutions should include widescreen ones.
But if you really dig 640x480, fixed aspect ratio is the best solution I guess :|