1. An Echange replacement. Not 8 things I can lash up to work but a single system that is easy to install that offers all the features of Exchange with none of the pain. Oh and it must work with Outlook and should have a good client that does everything Outlook does plus a good web interface.
Fully open source Exchange replacement is finally available, thanks to SOGo and Openchange people: http://www.sogo.nu/english.html
It's also awesome that it can use your existing IMAP server for mail storage rather than reimplementing its own. Also if you don't want to lash up 8 things together, they have all-in-one package you can install.