We're running 2007 and 2010 on our machines now...MS is really pushing the 365 version and I imagine I'll be forced to make that move for my next batch of laptops. I like 2010 a lot-huge improvement over 2003. I second the motion of checking out the Home and Student version if you want to stay with an office product and don't use it a ton(and commercially) Personally, I've tried many of the knockoffs-none serve the purpose for me that the real version does(albeit-I'm a commercial user that utilizes many features of Word Excel and Outlook daily)
A few reviews I've seen for Libre-Office compare it to the functionality of Office 2010 with a more limited user interface...