Mac OS X 10.6.2 is out.
It fixes quite a bit of issues, including a long-standing issue that I’ve had with Apple Remote Desktop, and its daemon build_hd_index freezing my machine for fifteen to thirty minutes every night at midnight.
It also fixes a rather nasty bug that deals with guest user accounts. In fact, if you have guest user accounts enabled, you should update immediately. Otherwise, I recommend waiting a few days for your production environments, for any new issues to float to the surface and get squashed.