The Masters don't give orders;
they work with everybody else.
When the job's done,
people are amazed at what they accomplished.

There are two major versions of the Mac OS in use today: OS 9.X and OS 10.X.
There are four major versions of Windows in use today: Win98, Win2000, WinME, WinXP.
And there is Linux.
There are seven browsers: Internet Explorer, Netscape 4.X, Netscape 6.X, Mozilla, Opera, Konquerer, AOL.
There are two primary screen resolutions in use today: 800x600 and 1024x768.

Consider the combinations! What good is your page if it looks great in IE 6 under Win XP at 1024x768 if your visitor is using Netscape 4.X under Mac OS 9 at 800x600? You will not have their trust, or respect, or traffic.

Work with everybody else. Your design should be—if not perfect—at least functional in a variety of browsers, on a variety of platforms, at a variety of resolutions. If you do this job correctly, all people will be amazed at what you accomplish in your design.