My iPad2 is on 5.0.1 with no problems so I would try doing what the others have said and doing a clean install BUT make sure you back up all your data first with iTunes.
To do a completely clean install/restore and use whatever firmware you want to use watch this
Restore iPad, iPhone, iPod Touch
the various previous and latest iOS firmware versions are here:
http://www.felixbruns.de/iPod/firmware/