5. Funkbox Drum Machine (iPhone, iPad, $2.99)
Sometimes all you really want is a straightforward beat without a lot of fancy manipulation options. That's where Funkbox, ahem, beats everyone else by a wide margin. It's chock-full of simple beats, with drum sample sources ranging from an MRK-2 to the TR-808. The bonus comes from the fact that's it's perfectly capable of kicking great beats straight out of the box. But for those who want to dig in, a fully functional editor is there, as well. Plus it kind of looks like those weird old drum machines that used to come built into electric organs.
4. Soundcloud (iPhone, Android, free)
Sure, the main purpose of Soundcloud on the iPhone is browsing, uploading and checking out new music. But it also has a record function for unbelievably easy file sharing that completely and totally blows everyone else out of the water. It seems utterly simple, but it's a great repository for people who have a lyric, a tune or a beat stuck in their head but don't have time to sit down and actually write the song. You can make a quick recording and check it out on your computer later.