I currently support 18 different companies and the majority of them are using office 2003. I have only 4 that uses office 2007 and there is not much differences between 2003 and 2007 except the looks and where they have eliminated some things in 2007 that were helpful. I have one system with 2010 and the classroom in my shop has both 2007 and 2010 to provide training. I will not be upgrading or recommend upgrading if in some cases, I have recommended open office and also have that installed on the training systems for classes to use.