If you've install a solid state drive (SSD) in your machine, and are running Mac OS 8.5 you may encounter issues when your computer sleeps. While I am yet to find out what exactly causes this I believe there is a bug which causes Mac OS 8.5 to crash some machines when an SSD has been installed. This may only be relevant to certain types of SSDs. I have found this to happen often with PATA/IDE > SD adapters.

The Fix: Updating to 8.6 solves the issue.