Samsung Galaxy S2 hangs/freezes sometime
If you suspect an app or service is causing the freeze, and if your phone is rooted, install Bloat Freezer and then freeze  background apps and services in groups to try and isolate the problem.
A good list of apps that can be safely frozen can be found here. Some of them are:


All share
Analog clock
Android live wallpapers
Ap Mobile
Bookstore


There are over a hundred listed in the post I've referenced.