Telus Milestone, stock 2.1-update1, rooted, lightly themed, but not overclocked... And no random reboots.
I did have a magnet-free case that would kill the battery in under 2 hours, and leave the battery cover uncomfortably warm. I determined it would only happen if the phone was "on" inside the case-- I'm guessing some button was being pressed.
Other than that, the phone's been solid. No auto-task killer (well, outside of the native OS), but I do have advanced task killer which I use on occasion.
... just another data point if anyone cares.