All modern monitors (mostly wide-screen) support at least 1280 x 1024 pixel resolution. In January 2010 76% of the computers where using a resolution higher than 1024 x 768 px.
1200 is divisible by 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 40, 48, 60, 80, 120, 150, 200, 240 and 400. This makes it a highly flexible base number to work with.
The 1200px Grid System is based on the 960 Grid System of Nathan Smith.
1200px grid
