I have a 17" HP Pavilion laptop & it gets very hot. I've gone through 4 cooling pads/fans. Is there a really good heavy duty cooling pad/fan out there?

the best laptop cooling pad is one that allows air to circulate. I tried one of the ones with the fan in it, and don't think it did much of a job. Sure it has fans, but they blow against the underside of the laptop in a spot where there are no intakes. Seems rather pointless, that. Right now I have mine on my bed and it's sitting on a box with the cpu side hanging over the edge. This puts my bottom intake grill out into the open air, greatly improving airflow. The cpu is running Folding At Home and stays around 40C. while doing so. Very cool for a laptop, they are notorious for heat.
Were I to get another pad, I would try something along the lines of this Trimex
It would allow for better air circulation under the laptop.
And the biggest thing you can do to keep your laptop running cool is to keep it clean. Dust will clog the vents in no time, reduced airflow means more heat staying inside the laptop instead of being blown out. Use a can of air and blow those vents out now and again.