When I first started to work with Microsoft Office 2007, one thing I wasn't too sure about was the ribbon. I was a bit worried that, in spite of the added structure it provided and the nifty on-the-fly preview of style changes, finding what I was looking for would be a bit hard.
Turns out that the only section of the ribbon I had any trouble with was, well, the Home tab. That's because all the other tabs have fairly descriptive names and I found myself quickly able to guess what features I could get under each. Problem with the "Home" tab is, it is intended to be a hodgepodge of the most common features, which means that it could potentially hold pretty much any type of features. On the other hand, since there is only one such "catch all" tab, I never had to look at more it and another one to find what I am looking for.
One trick that took me a few days of usage to realize is that you can right-click on any ribbon icon and add it to the quick-access toolbar (at the same level as the "save" disk icon on the picture). That's pretty cool, and very efficient too.