Well, I currently run both Open Office 3.1 (on my Linux Laptop) and MS Office 2007 on my (Windows Laptop). As much as I am for open source, I cannot stand open office, it is way behind the development of MS Office. The funtionality is not always there, especially in Open Office Impress (The powerpoint competitor), I have to read a lot of power point documents and everyone is making them in office 07 now in the pptx format and Impress just rips them apart.
But one tip I have to you, since you are now using open office, when you plan to send a document to someone else who may not be running open office, save the document as a PDF, that way when they open it all the formatting will be exactly the same. I have had problems in the past where I spend lots of time fixing the formatting in my Open Office Document just to have it look like crap when someone opens it with Word.