I'm liking IE7 a lot.  It is much improved over the previous version(s), but I've come across two annoyances that I have not seen reported in the forums.  Here are the repros:

Hang when Closing with Multiple Tabs from the Taskbar

1. Verify that the "Do not warn me when closing multiple tabs" is unchecked (aside: "negative" options are confusing.  This should probably read "Warn me when closing multiple tabs" and should be checked by default)
   
    
    
2. Open two or more tabs to any URL
   
    
    
3. Minimize IE
   
4. Close the instance of IE from the taskbar using the context menu
   
   
     
5. IE will hang because the modal dialog that is asking to close all the tabs is not visible
   

The Disabled Back Button

Sometimes the back button does not enable when it should.

1. Navigate to http://www.google.com
2. Do a Google search (on "AJAX" for example)
3. Though navigated to the search results, the back button is still disabled
4. Go to the next page of search results - the back button is still disabled