Unless you need it for work, I wouldn't bother. Also Office 2010 is in beta right now, you might be able to ride the beta for a bit. Open Office works fine if you need the tools. Google Docs is out there for basic stuff too. Lots of options to Office, and yes it is not cheap even for one copy. Office online is coming or here (have not looked into it), but it will more than likely cost money too.

Why do you need Office?

Oh and Win7 does not include Office (why would they give away that $)