Capture - Quick Video Camera for iPhone
An answer to many a parent's prayer when trying to get video of their kid doing the cutestthingeveromgdidyouseethat only to have to wait for the Camera app to start-up, by which point your kid has stopped doing the cutestthingeveromgdidyouseethat.
Capture starts recording as soon as you launch the app and stops when you press the home button. Your video gets added to the default Camera Roll just like the native Camera app. Slick.