There is now a really easy way to provide feedback as you are using Office 2007. Directly from Joe Friend's blog:

Sending Feedback

We have a great program called "Send a Smile" that provides you the opportunity to tell us what you think about the product. Don't worry you can "Send a Frown" too! Just download the SaS application and install it, then as you are using the product and experience something you love/hate you can simply click on the smile or frown in the notification area at the bottom right of your screen:

Next you'll see a dialog that includes a screenshot of the current application in use and a text entry box to include your comment. You can choose not to send the screenshot if you so wish or you can update it to make sure it shows the issue you're writing about. The more details you put in your comment the better. Click on the image below to see what this dialog looks like.

What happens to this information once you submit it?

The information (your comment and screenshot) is forwarded on to the Office team. We evaluate the comment/screenshot and make sure it gets routed to the correct team. Then we evaluate the information in order to determine if there are changes we need to make to the product. FWIW, we expect to get a lot of feedback, so it we can't respond directly to most, but we will be reading it as fast as we can.

So, download Office, load SaS and tell us what you're thinking!