defintly Mobile Defense, it's free and a good idea, it'll even track where the phone is as well as lock it. could be handy if it were stolen to have the address where it was taken to. Handcent is WAY better than the stock messaging app, Shazam is handy if you listen to the radio alot and want to know the name of a song, I use PDAnet quite a bit to get my laptop online with my phone