Just chiming in - I've been getting random reboots since the last update as well.
Stock OTA. I'm now rooted (wasn't during the OTA), and running SetCPU, but only for some powersaving settings. No overclock. Reboots occur when none of those settings would be in effect anyway (<20% batt, or high temps, etc).
Had reboots while running LauncherPro, so I removed it, and went back to stock. Still get reboots.
Did a factory reset, and reformat of the SD card. Still get reboots, and at the same rate. Even before reapplying root, SetCPU, most apps.
I've more or less given up. Hoping an OS update will fix it. If not, I'll ride it out until I'm due for a phone upgrade.