mack - 8:34 pm on Dec 18, 2012 (gmt 0)
I think I will do as you did and upgrade to 12.10 also going to cut back on some rarely (once in a blue moon) used applications.
Funny you mention Thunderbird as a potential problem source. I only installed that around about three months ago, and that kinda ties into the time frame of when my problems started.
Did you continue to run thunderbird after you updated?