ios5 contacts hang the phone app

I upgraded my iPhone 4 (just got it early this summer) to ios5 yesterday as soon as it came out. Now I can't view my contacts on the phone - it hangs the phone app.

The only way I can recover is to hit the home button, find the running program with the Home double-tap, then kill it and relaunch. Turned the phone off then on again, same result.

Someone suggested resyncing the phone and I did that but it didn't help. I turned off sending my phone contacts to the cloud but that didn't help either.

Is this a bug or is something up with my phone or with the upgrade?

Thanks in advance!