For those who are still designing web sites that are non-static, a good thing to know is "What will the site look like in 800x600?" and you are in 1280x1024 or 1024x768.
No fear there is an easy way!
In the URL bar of your web browser type in
javascript:resizeTo(800,600)
Now you will see what the site looks like in an 800x600 window!