Best Apps For Your New Chromebook?

The Verge has a story stream for the best apps for your new devices, but they left out the chromebook. I am ordering a new chromebook today. For those of you who have one, do you use a lot of apps? What are your favorites?

Here are some categories:

1. Productivity

2. Personalization

3. Games

4. Photo Editing

5. Calendars, Task List, etc...

6. Communications/Social Networks

7. Browser Extensions

8. Other?