It's really amazing how good the word recognition works. In english and even in german! Much easier to dictate and the correct some errors than typing long sentences on the iPhone's keyboard.
We are using Yammer In our company as a knowledge sharing tool. The iPhone App however is not very comfortable to use. That's why I prefer the web interface.
Good for cropping and rotating pictures. Integrates well with facebook so I often use it to upload pics to facebook instead of using their crappy application. Only drawback: All pics will be published in the same folder.