Well, maybe not completely innocent. Here's the story: A little bit ago, I claimed that uninstalling Parallels from my system had solved some instability problems I was having. Not so fast. I'd gone five days when I wrote that post without seeing any evidence of the instability after removing the drivers. The next day they came back.
What did change was that my erratic mouse problem went a way permanently, so I still believe that vmmain.kext was the cause of that. But it wasn't causing the freezing. As I said, that returned and kept happening.
I began to suspect that it was a memory issue since there were no third party kernel extensions left to uninstall and the visible behavior was not something I'd attribute to a application (overall system hanging with frequent accompanying high CPU load). It felt like a tight loop in privileged code.
So, my latest theory is that it's related to memory. I've now gone a week without a problem after pulling the memory and replacing it with new DIMMs. The only problem is that I only had 3Gb of replacement RAM so I went from 4 to 3Gb. If this really does solve my instability problem, then I will have to determine whether the memory is really bad or if it's something to do with having 4Gb in my machine. Another option is that it's thermal and having 4Gb of memory pushes it over the top on temperature. Isn't this fun?