My favorite Android app is Documents To Go. As a police officer I have to do many reports. If I am not near a computer, I can write the report in Word on my phone and then email it to my work email address. As a Police Sergeant, I use the same app for scheduling and other important documents that I may need when out in the field and not near my desk.
Android in general has helped in my job in so many ways from Google Maps, Vlingo, browser, camera, different Cop apps and even Angry Birds during boring meetings.