I have the Nexus S, I'm running  2.3.4 and it's the build of GRJ22.

When I turn the phone on, it doesn't always reboot.   Pressing the power button gets a startup vibration, the Google logo appears, then the home buttons light up.  The Google logo flashes a few times, then nothing more happens.  Buttons are unresponsive.   A battery pop and a retry (multiple times) eventually triggers a normal boot.   I've seen this occur when I've simply powered off, and I think also after a full batter discharge.

(I did have the freezing problem, but the 2.3.4 update corrected that when I applied it a few weeks ago)