Can you use both on the same machine, without causing issue with each other? I need to keep my 04' so that my own docs from my macbook, my old pc, and friends that haven't updated yet. I should add 08' so my instructors don't have to jump through hoops to read my email attachments. Because as I understand it the file format on the new office mac 08' is now .docx is that right? i can get a full pro version of 08' from school for 60$ so cost isn't part of the equation. I am just really indecisive. Thanks for any help you can offer!