9GAG is a community based hilarity engine driven by mindless cat obsessed drones. Well, not really. But it is an awesome place to find some laughs. The app, although not really tablet optimized, works well for a larger screen.
I never was a Google Reader guy; the only aggregator I've used is in the past was Flipboard. Now I'm split between Feedly and Flipboard. Feedly just has an awesome interface, and works great on my tablet.
In my opinion, the forthcoming go-to file manager for Android. Despite being an young project, it is a fully functioning offline file browser, with excellent design and a clear user interface. The best part? It is complete free. No ads. Awesome.