I use OpenOffice as my office tools suite. For my needs -- letters, documentation, and budgets -- it is more than adequate. The one area where it is not nearly as good as Microsoft Office during collaborative writing and editing. Word's balloon comments really makes it easy to add and review comments and maintain the integrity of the original document.
I did find one feature in OpenOffice recently that helps collaboration though and that is line numbers. OpenOffice will automatically add and maintain line numbers in the left margin. This feature makes referencing the content in text -- email, IM, etc -- and in person -- meetings, phone, skype, etc -- straigh forward. I wish Word had this feature. Then again, perhaps it does and just have not yet found it.