I use SMC Fan Control to keep my fan at 6200 RPM when it's plugged in. That usually keeps my temps around 60 C. It's my understanding, too, that keeping the fan so fast and the temps cooler will prolong the life of my mac. When the mac is on battery power, it runs hotter because the fan goes slower to save power. But 95% of the time it's on wall power anyway. Low-tech solutions for not frying your legs include putting a pillow or blanket between your lap and your laptop.