Microsoft Project

Project 2007 has multiple level undo. It is worth upgrading just for that!

Project 2007 has much the same functionality and appearance as 2003. It is the only application in the 2007 Office suite which does not use the ribbon!

Project 2007 saves in xml format - you will need to downsave it for users of earlier versions to be able to read it.

Most of the templates on Microsoft's site are now in 2007 format. Without a converter (downloadable on the MS site) you won't be able to use them with 2003.