Had this yesterday, found a little guide somewhere which went as follows:
1. Open any app
2. Press and hold the power button until the slide bar appears
3. Press and hold the home button until you return to the home screen.
I had to do 2 & 3 a couple of times before it went back to the home screen (seems theres a bit of a knack to it).
Home button seems more responsive, but not sure whether it's my mind playnig tricks.
Supposedly it recalibrates the home button...