Plaxo Toolbar for Outlook
I use Microsoft Outlook at work and at home for managing contacts, tasks and memos. I've tried various approaches to keeping these in sync. When I regularly carried a Palm, I would sync to the Palm from home and work. But this was inconvenient and I would often forget. I also tried Yahoo Intellisync for a time, but found it to be buggy, reporting errors that I couldn't trace down and fix.
After reading Getting Things Done (GTD) by David Allen, I began relying upon Outlook Tasks even more. So I needed to find a reliable approach to keeping these uptodate and in sync. I have been using Plaxo for a while to keep my address book uptodate, and discovered that their Outlook Toolbar allowed you to sync Outlook calendar, contacts, tasks and memos with the Plaxo server.
So by simply installing this both at work and at home, I am now able to keep in sync. So far I have found it to be 100% reliable, and have had none of the strange errors or duplicates that plagued me with both the Palm and Yahoo Intellisync approaches. At first I had it prompt me each time it wanted to create or delete an entry. But after a few weeks of never needing to correct it, I've since checked the box so that it can just go ahead without prompting.
I still sync separately with my Palm and my cell phone, but these are now 1-way synchronizations from Outlook to the device.