Please don't ruin Windows 8 with ribbons. As soon as I heard that they were going to be scattered all over the place I was immediately put off by the decision and will chose to stick with Windows 7.
I don't care how much faster you make it. I don't care what sort of neat tools add or fancy animations you slather on.
The ribbons suck. Please understand this.
Oh but the ribbons make everything easy to access!
Please refer to the Search Commands plugin from OfficeLabs.
You know there’s a button for it, but you don’t know or remember where it is. If this ever happens to you, check out Search Commands.
Wait a second, wasn't this the problem that the ribbons were DESIGNED to solve?
The ribbons will improve efficiency
According to the results of this survey from ExcelUser.com, no they don't.
People who have used it for a while love the Ribbon
A teaser link to a blogpost by Jensen Harris, Office User Experience Manager, called "The Story of the Ribbon" brings a whole heap of comments from frustrated users.
Many of which have tried Office 2007 and either reverted back to Office 2003 or gone to an Office alternative such as Google Docs or Open Office.
Also, companies are opting NOT to use Office 2007. With big companies with as many staff as 150,000 worldwide, this is a huge mistake on behalf of Microsoft. Think of all the rupees they're losing out on!
There are more arguments here, it's pretty entertaining.