Quote of the day comes from Nick Finck:
"Finding a balance is the key to a true solution, fixing the width is only a temporary Band-Aid."
He also points to one of my favourite ever articles at A List Apart, A Dao Of Web Design:
"Make pages which are accessible, regardless of the browser, platform or screen that your reader chooses or must use to access your pages."
Cast off your fixed-width layouts; you have nothing to lose but your WYSIWYG mentality!