For my email and calendaring, I use Mozilla Thunderbird with the Lightning plugin (which implements the Sunbird calendar inside Thunderbird – nifty!).
As you can see here, Lightning is helping me plan my morning at work efficiently, by automatically checking over 4 billion of my calendars. Perhaps by that time it has fetched all of that metadata, I’ll have been lucky enough to miss my first meeting 🙂
Jonathan Gazeley 