A fine (and growing) list – now you just have to keep the school teachers away.
I’ve been intimate with Open Office, SugarCRM, ActiveCollab, vBulletin, and of course Linux and MySQL. I don’t consider Google Analytics open source, but it is certainly great value. Of them all, I couldn’t live without MySQL anymore – it (along with PHP) has replaced spreadsheets for big data analysis tasks on this desktop (yea, MS expanded Excel to a million rows…too late).
Why isn’t there a serious ERP competitor in here yet?