CTRL + F11 in Opera is the best.

Btw, I found this Greasemonkey script for Firefox users. It stops page widening caused by code and img tags on a phpbb forum I visit.
// Sweclockers page widening fix
// version 0.6
// 2005-05-23 Sebastian Jansson
// License: Creative Commons Attribution-NonCommercial-ShareAlike License
// http://creativecommons.org/licenses/by-nc-sa/2.0/
// --------------------------------------------------------------------
//
// ==UserScript==
// @name Sweclockers page widening fix
// @namespace http://jonex.1go.dk/greasemonkey/
// @description Stops page widening caused by code and img tags.
// @include http://forum.sweclockers.com/*
// ==/UserScript==
function addGlobalStyle(css) {
var head, style;
head = document.getElementsByTagName('head')[0];
style = document.createElement('style');
style.type = 'text/css';
style.innerHTML = css;
head.appendChild(style);
}
function addFixStyles() {
var maxwidth = window.innerWidth - 250;
var css = "\
blockquote {margin: 1em 0.5em 1em 1.5em; padding: 0;}\n\
pre { overflow: auto; max-width: 500px; }\n\
img { max-width: 500px; }";
addGlobalStyle(css);
}
function addFixScript(){
var head, script;
head = document.getElementsByTagName('head')[0];
script = document.createElement('script');
script.type = 'text/javascript';
script.innerHTML ="\
function fixWidth() {\n\
var maxwidth = window.innerWidth - 244;\n\
var fixRules = document.styleSheets[1].cssRules;\n\
fixRules[1].style.maxWidth = maxwidth;\n\
fixRules[2].style.maxWidth = maxwidth;\n }";
head.appendChild(script);
}
function fixWidth() {
var maxwidth = window.innerWidth - 244;
var fixRules = document.styleSheets[1].cssRules;
fixRules[1].style.maxWidth = maxwidth;
fixRules[2].style.maxWidth = maxwidth;
}
//Executes at start:
document.getElementsByTagName('body')[0].setAttribute('onResize','fixWidth();');
addFixStyles();
addFixScript();
fixWidth();
I belive it must be modified. But I leave that to someone with better javascript knowledge than me.