Google Calendar, an overwhelming Lifehacker Hive Five winner.

With more than half of all votes, Google Calendar won by a landslide against Apple's iCal, Microsoft's Outlook, Mozilla's Thunderbird and specialized app Rainlendar, this past week.

And today, Google Calendar implemented changes to its look with simplified UI, making it nicely scalable on different screens.  Love the clean, new look...I wonder if this has anything to do with former Macintosh designer Andy Hertzfeld's influence?  He's apparently the force behind the wheels in Google+.

That background image, by the way, was made possible by clicking on the options menu and selecting Labs, and enabling the background feature.