When using the Blueband masterpage or a custom masterpage, you may find that the drop-down menus don’t work in Internet Explorer 8 (IE8).
There is a fix for internet explorer or you can view the page in compatibility mode. The only problem is you can’t expect all your users to know how to do this. Your site will be unusable to some of your users.
To fix this problem include the following meta tag into your masterpage:
<meta http-equiv=”X-UA-Compatible” content=”IE=EmulateIE7″ />
It will force IE8 to render the page as it would if it was still IE7. Maybe not the best of fixes but all that Microsoft provide at the moment. The SP2 update to sharepoint just adds this line into the Masterpages (this will not add it into custom masterpages that you have already made!).