One of the more important features of any mobile phone, let me show you how to set an alarm so it will only ring on the specific days and not on weekends when you need your sleep the most.
Really great and free service where you can chat using a bunch of services like Skype or Google Talk within your web browser, meaning you don't need to install anything on your computer.
In this day of age, it's very practical to have a Windows 7 installation on your USB key, for many netbooks and devices don't come with CD/DVD drives anymore.
Remember the legendary Predator movie with Arnold Schwarzenegger? Those Predator aliens had this thermal view feature so they could their prey even in complete darkness, let's Photoshop it.
If you activated the new Inbox Tabs then after a while you find yourself not liking them that much and would like you old priority inbox back, this is what you need to do.