There might be one caveat on this - not sure when the versions changed this, but new(er) versions of Word save as .docx - which is not readable on older versions of Office. This has been causing headaches at my office, which is based on Win2K, Office 2000 installs.
I've not had enough of a go with Office 2007 (reinstalling it as I type) to see if you can change the "save as" format (I'm sure you can) but it might be worth bearing in mind if you are using 2 versions of Office at home/work/school - as far as I remember, this is the first time such a problem has occured with incompatabilities.
I know you can get software to view .docx files if you are running older versions of Office, but our Stasi-esque admin policies allow no such tomfoolery.