I have the same problem with my 3G Touch. Sometimes you single press the home button and it registers as a double press. Sometimes I double press and nothing happens. Sometimes I press (or double press) and it takes a couple seconds for anything to happen. If I'm listening to a song and I want to go back to the playlist screen, I sometimes find myself repeatedly stabbing the back arrow at the top left of the screen, waiting for it to register. I probably could press it once and then wait for a couple seconds, but since it appears to be doing nothing, I end up tapping it quickly in succession.