I use the Derman version of Fan Control and love the ability to manipulate the fan cooling. I don't use SmcFanControl because that only jacks up the fan speed during idle peroids but does progressively less as the temperature rises; it'll just keep the fans running faster all of the time. My thinking on the default cooling curve in a Macbook Pro is geared towards lower power consumption and possibly quieter operation by favoring lower fan speeds. And some Macbook Pros are prone to early failure easier than others like the ones using the Nvidia 8600 GT GPU. The down side of the default settings is that it will shorten the life of the CPU, GPU, and hard drive. There is a trade off to altering the fan cooling curve but it's of no real consequence if you're moderate about the settings. Here's the pros and cons as I see it:
Pros:
Lower internal temperatures
Extended CPU, GPU, hard drive life
Cons:
More fan wear
More air particles circulated internally
Slightly higher power consumption
More fan noise
In my opinion the pros well outweigh the cons. My Macbook Pro Fan Control settings are set to where the fans run at default speeds most of the time but as the temperature rises from heavy use the fans run at increasingly faster speeds and my maximum temperature is set down to 85°C. With my settings the fans don't see any increase of use unless things are getting hot.
My Fan Control Settings:
Low Temp Thres: 55
Upper Temp Thres: 85
Slow Fan Speed: 1200
