As IE7 approaches release, the IE team has released a detailed list of the 200+ CSS changes that will appear in the final release. If you do any web development, this is a great time to read the list and audit the CSS that your sites use. IE7 breaks many of the old hacks used to work around the bugs in previous versions, so careful attention will be needed to ensure everything keeps working and looking as intended.
IE7 is a major step forward, and all web developers owe the IE team a ’thanks’ for being so transparent in this process and making detailed change lists such as this one available.