NOT.

My wife just built a new design for one of our sites. We develop on Linux and test with Firefox and Chrome, but we decided to break out my work laptop (Windows 7) and try with the browsers there.

Chrome....Fine.

Safari...Fine.

Firefox....Fine.

IE8.....

Oh dear.

IE8 was the only browser to render the site incorrectly.

However, turning on IE7 compatibility mode made it display correctly. Microsoft provide the following meta tag that you can add to the head tag to turn this mode on by default:

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />

Once we'd added this everything was fine in all browsers.