If you want to know what some of the latest sitings of IE7-caused problems are, you might be interested in reading some of the posts on SitePoint . And I'm sure these just the beginning.

So far, most sites that have has their pages validated properly are not having any major issues. But older sites may start to find some, since IE7 supposedly has incorporated a lot of the standards that all the other browsers live by. This means that it's not going to "fix" so much of that poorly done code, which it has done in the past. It doesn't mean that every site that's older is going to break, but it does mean if your site happens to use code that wasn't all it should be, you could start seeing and/or hearing of problems with your site. If you do, know who to blame... not your web designer, but the company that has always run rough-shod over the standards and insisted on creating their own, whether or not they made any real sense.

In the meantime we are all trying to figure out just what has changed.. even the experts, the big companies, are having problems with this newest entry, so it may take some time yet before the workarounds are figured out. In the meantime, if your site is working just fine, then be thankful that once more you have gotten past the Microsoft gauntlet.