If you are still running Office 2007 Beta 2 Technical Refresh it will be important that you mark March 31, 2007 and May 15, 2007 on your calendar. On March 31st, the client builds of Office 2007 will expire. Then on May 15th, the server builds will expire.
I have personally been involved with Office since Office 4. My first product involvement was with Excel 4.0. I've seen many iterations of Office and this particular release really has me excited. I will be the first to admit that the new UI was a bit intimidating to me at first, however after using the product for a couple of days you begin to realize just how much easier the new UI is over the old menu system in previous versions of Office.
To learn about the different Office Suites checkout http://office.microsoft.com/en-us/suites/FX101677751033.aspx.