Android User? Your indispensible applications?

What are the apps that you find most useful?<br /><br />I go for Handcent SMS, Barcode Scanner, ShopSavvy and Shazam.  Looking for other opinions to see what I could add to my repetoire.<br /><br />Oh, and if you're interested in a bit of useful fun, Smart Measure and Smart Protractor are really cool, and work too!<br /><br /><br />