If you really want to 'wow' yourself with your new tablet, try installing VNC. It'll allow you to take control of your desktop computer and see it's screen on your tablet.

Becomeroot is always a plus as a lot of the cool things you can do might need root access. Just be careful, you don't want to turn your new tablet into an expensive paperweight.

Installing Canola is a definite plus, it gives the tablet a nice polished interface for playing movies, music, and viewing pictures.

Otherwise, application-wise, it's pretty much up to you. I only have a 770, and the way I use it has changed about 20 times over the past two years. Now it's mainly media-on-the-go.