I also am using MS Office 2007. It works for me but I am not really happy with it. I think MS Office 2003 (especiall MS Word and Excel) is simpler and more user friendly. It's just me though.
Why pay for MS stuff? I use Open Office, I does the exact same things (even in excel), and crosses over well with other programs.
I use mostly the office provided on windows phones and Windows live. I don't do a whole lot of in depth word processing so it is enough. 2 of my computers have office 2000 (i think) on them but my wife mostly uses those for whatever she needs.