I've been monitoring this thread since it started. Seems like we all have similiar issues with different causes.
I typically get 1-4 reboots a day, working 8 hours on a 2008 Mac Pro using Mavricks. The reboots I experience all happen when using Adobe Illustrator (CC) when I save, only Illustrator, only when saving, which I should add is to a SMB attached network volume.
I wanted to add to this thread that for the past 2 days I have disabled Google Drive and I have not had a single reboot since, and I have been using Illustrator heavily. It used to reboot about 25% of the time I did a save, and I must have saved 30 times in the past 2 days with zero reboots.
My two cents. I have a team of 6 Mac users here at work that I don't want to upgrade, or even get the new Mac Pros for if there's even a chance this'll happen. This needs to be addressed.
Edit: FWIW, I have no attached USB devices other than mouse & keyboard, and Time Machine is disabled.