Today, running SS4.7 (Froyo), with the 1.0GHz LV kernel. Running SetCPU with temperature profiles set up to passively update (to save battery).
I had my phone in my car dock and hooked up to the (genuine Motorola) car charger. The car dock app was running, and I was running Trapster. I always knew that app to be power hungry, but this time it was too much...The battery started at > 90% when I started driving, and within 1/2 hour my overheat profile kicked in (temp was up to 138F). That was well above my 125F setpoint, so I guess the passive polling just didn't catch it in time.
Also noticed that by this time the battery was drawn down to 60%! So Trapster was using FAR more juice than even the charger can provide! I knew it was crazy with the GPS usage, but between GPS and updating the map it was turning my Droid into a nuclear "NEW-cue-lurr" fusion device! Good thing I had SetCPU profiles enabled, or I would have fried my Droid!
My advice is to use GPS-intensive apps VERY sparingly, and if you must, crank down the clock speed as much as you can tolerate (I will be UNDERCLOCKING to 400MHz or even 250MHz if I ever run Trapster again). And ALWAYS run SetCPU with temp profiles, even if your ROM will "take care of the clock speed for you"