What’s the difference: {hsize, linewidth, textwidth, pagewidth}?
There are many more lengths useful to layout in LaTeX. The ones related to “page” layout are mostly here: http://en.wikibooks.org/wiki/LaTeX/Page_Layout \linewidth is width of text in current environment. I myself am not sure about how \hsize relates to the others, although I think it’s supposed to be the width of text on the page.