1) Google Currents- Such a vast amount of interesting periodicals to browse through, and a selection that is broad enough to spend hours flicking through.
2) ADownloader- The best torrent downloader for android in my opinion. I mostly use it for movie night w/ the Wife, & audio books which I like to listen to as I drift off to sleep. (Tip- If your torrent is downloading slow, try opening the browser & loading a couple of heavy web pages. This seems to expand the bandwidth & at least double their speed.)
3) Tunein Radio- So many stations from around the world, but I generally listen to the podcasts.
Honorable mentions- Music Paradise, YouTube(probably my Fav, but too obvious for the top 3), Distro by Engadget, Mybidder auction sniper for ebay, Craigslist HD, Overskreen Browser, Allrecipes, & Tablet CPU usage...
Holy Smokes.... I could go on forever here!!!