I use mine for listening to music. It makes a great desktop radio if you own TuneIn Pro. It doesn't use much battery at all.
I also use it for Reading. I use Mantano as my default reading app. It's an epub reader but it allows me to change the background color and brightness of the book so I can read comfortable. I do this before bed each night. Read about 3 to 5 chapters so I can wind down and sleep.
I surf alot. Facebook works great on Silk. I use the Pulse app for my Google reader and so I can up to date on my RSS feeds and then I have Opera Mobile for other surfing sites that Silk doesn't like. I also listen to podcasts.
I have watched a few videos and played Angry birds when I am bored.
I even use it for recipes. I use Google docs for my recipes so I can use the Quick Office app to access them when I am cooking.