Falling into the category of “useful tools that there wouldn’t be any need for in a perfect world”, here’s a neat site that renders a url to preview how badly your lovingly-crafted CSS gets mangled by IEs 5.5, 6 and 7.
Of course, if standards actually meant standard, then this wouldn’t be needed - but in the meantime it could save some wailing and gnashing of teeth. Basically you bang in the URL of your page, and then you can preview the effect of rendering in each of the versions. There’s also an overlay mode which shows the pixel-by-pixel differences between 6 and 7.
