Be sure to blow clean the shared heat sink for the CPU/GPU once you have the keyboard off. Minimizing heat cycling will lessen the chance of the failure .... I bring my unit down to it's lowest power level setting using Power Manager and let it idle that way all day when not in use and then over-night it in Standby mode ..... rebooting only once every few days or so.
It is always docked and rarely goes cold to save a few watts of energy primarily because I'm no Al Gore fan.
Neither am I, but who are a fan of that guy these days ? I find Alex Jones' movies much more revealing than Al Gore, but that's a sidenote.
I've had ThinkPads since 1998 so I'm used to take'em apart and they'll usually get the full cleanup once they're opened.
This machine is on full throttle and the aggressive TPfan-setting takes care of the rest.
Just took a trip with the Google Earth Flight Simulator in fullscreen mode (F11) and I couldn't get the GPU over 47-48 C in TPfan, toggling back and forth just to check.
Also, during fullscreen viewing of a 1280x720 HDTV broadcast, the temperature never exceeded 48 C in TPfan. Running in the background gives 46 C.
Of course, this can only be done will full clearence of the inlets in the bottom of the machine. Once these are covered or the fan outlets are blocked, the temperature can rise considerably. I've given the machine some filted 4 mm stickypads on the bottom and are using the machine on a daily basis on top of a thin (3-4 mm) plate of plywood so it can be used as a Laptop without blocking any vents.
In other words, I keep the machine cool
, but with full throttle.
 All in all, the machine is kept between 43 C (idle) and 48 C (roadrunner) whenever it's fired up. Standby when not in use. Rebooting perhaps twice a month.
Oh, and by the way. The battery is kept between 30-52 %. Never at 100% and only if it's forgotten, it occationally gets to deepcycle at 18-20%. Even after a full year of service, it still got 91% capacity. (Estimated. Machine bought in July 2010 with a used battery) At least 8 months in any case. It has lost a few percentage since.