Two apps that I think any Android owner must get are Dropbox and Widgetlocker. Widget lock costs you $2 but it'll be the best $2 you'll ever spend. It allows you to put widget shortcuts directly on your lock screen. Dropbox is a cloud base storage where you can sync your phone/computer with the same files. You get 2GB for free. This is my referral if you want to sign up with that, you will get an additional 250MB
That's all I got, hope it'll be a start to your Android addiction.