I have this issue with an iPhone 4S ios5 I was just about to post it but I found your thread, just curious as this only started happening to me once I set the alarm, and this only starts happening to me once the alarm has gone off in the morning before that it is fine but after that all of my apps will open but for like 3-4 seconds and then a blank screen and back to the home page I go, the only way around it for me is to turn off location settings and shutdown the phone and switch it back on, and then turn location setting back on and everything works fine.
I've been experimenting with selective location settings but no luck so far.