Two scenarios & Two solutions
Scenario one: the height is more important
Reasons could be
- you want your site to fit the screen without the need to scroll down (no vertical scrollbar)
- you want to be sure a particular image is visible (or text can be read) without using the scrollbar (but the scrollbar is available)
Scenario two: the width is more important
You want to fit your site nicely within the available width, and you don't care about the height because there's a scrollbar when needed.
For instance: a site with long text paragraphs (and lots of information on one page, like this site)
For instance: a site with long text paragraphs (and lots of information on one page, like this site)