Just a warning.. if you install Office 2010 Beta it will mess up Mozilla
Thunderbird! Atleast it did for me.

My settings are still fine, my emails are still there, but without waring it
did the following:

I had it pinned on the top of my Start menu, it removed it and replaced it
with Outlook 2010. I had it on the Quickstart menu, which it changed to
Outlook also..

I've already seen enough to make me want to not use the product. They're
redesigned the ribbon a little, but I like the "pizza wheel". They removed
that and made it a plain button now.

When uninstalling it replaced my Thunderbird quickstart with an Outlook icon
and changed the shortcut to open Internet Properties.