How productive are you with your devices?

The Nexus 7 has been known to be great for reading and such because of its narrow size. But I want to do better, and use my Nexus 7 more like how iPad users use their iPads - type documents/notes, edit photos - do actual work on it.

With the recent release of Simplenote, I've been using it a lot - but I find that even when we already have gigantic apps like Evernote that can do everything, we still like to look for apps that "do one thing". So I want to know... what apps do you use to be productive on your tablets (or phones)? Writing, sketching, reading, or anything to help you get work done?