You can have both on your machine 2003 and 2007. I'm using 2007. Outlook is not much different to 2003. The others have changed. I'm not a heavy user of any of them, though I have been in the past and after a year with 2007 I find I'm still searching for things I know are there, but have been moved. Kind of annoying. I dunno about anyone else but I find Word and Excel a lot slower to open then 2003 version, even on a decent PC. I don't find it any better to use than 2003 all this ribbon malarky is change for change sake IMO.