Background to fill empty screen area

[manvbf]

Hi,

I've got a web template coded to a fixed width of 800 pixels. When the monitor is set to 1024*768 or higher, the template design is centered, with lots of empty (white) space around. However, the design features some bright colored and white areas that sort of makes it "blend in" with the white space, so I need some sort of border or background to offset this and make the whole thing look better...

How can I add a background or border that will make the page design stand out from the empty white space?