Mr Big, 
5/1/2007
Office 2007 is quite different from the last version of Microsoft Office that I purchased, Office 2003. They have a new ribbon layout instead of menus that takes some getting used to, but once you use it for awhile, you will probably like it better.
Some really great features that stand out in my mind... Have you ever noticed how automatic indenting for lists or paragraphs didn't quite work right if you deviate from a sequential flow when typing out the list. (e.g. skipping around, going back, inserting in the middle, copying from other sections,etc) Well, believe it or not, this is fixed in Office 2007! It sounds pretty small, but given all the outline style documents I write, this turns out to be a real time saver.
Another cool feature for me... Excel supports 1 million rows of data! Previous versions truncated tables at about 64,000 rows. I tend to number crunch some really big data tables, so this feature has made my life much simplier. I could load these files into a regular text editor, but having them in excel with its nice formatting is soo much better.
I could go on with more and more features, but I'll stop. In my opinion, Office 2007 is worth the price.