Office 2007 is great, we use it site wide here. A couple of comments on it.
- Training was very easy, just a quick 30min session was all our staff needed to get used to the new ribbon. Zero issues since then.
- Filesizes are smaller, DOCX and XLSX are now default for our school and no one really notices the difference. Our backup has reduced significantly since we made them default. Only problems we have had is people sending files to the council or home, but this is very minor and its easy to save things in 2003 format as it has a massive button on the save as dialogue
- Hardware needed to run office 2007 is a little bigger but some extra ram was needed in a few of our older machines. We recomend 512mb as standard now.
- Works well with sharepoint and integrates nicely with it as an internal VLE
- Passwords are more secure and not as easy to hack.
- 2007 is alot easier to install manually

copy and paste the cd key is a god send!