If you are looking for an alternative to Microsoft Office Outlook I would recommend IBM Lotus Notes 8.5, it comes with a thee application Office Suite called Lotus Symphony that consists of Symphony Documents, Symphony Presentations and Symphony Spreadsheets.
I’ve still not worked out how to set it up for non IBM Lotus Domino server use, but since I’ve also got a copy of IBM Lotus Domino Server 8.5 I’ll probably add that to my server project along side Microsoft Exchange.
When you first run Lotus Notes after Installation you get the choice of using it with a Domino Server or as a standard PIM application.
Roland