Hi Technicks,
Like others have suggested, the most likely reason for your inability to control your fans with SpeedFan is that your motherboard simply doesn't provide support for this (which is often the case).
If you want to make sure, the SpeedFan site provides a list of supported hardware, including what kind of monitoring and control the different motherboards provides. If you board is not listed here, Alfredo (the SpeedFan programmer) is usually more than happy to implement support for it, if you just send him a "repport" (see the SpeedFan "Info" tab).
While I'm sure you can get lots of hardware regulators, to my knowledge none of these will provide the same level of control as SpeedFan, most notably there is no easy way for such hardware to read the internal temperature sensor, present on most CPU's (and some GPU's). Since these provide a much quicker temperature response, you won't risk overheating due to the time-lack often seen with external sensors.
If you are lucky, you motherboard may have a connector for the SMBus, in which case you might be able to find a fan-speed regulator that will plug into this connector, which should then be detected by SpeedFan (though I've never tried this myself, so..?)
The reason I'm using SpeedFan is a bit more "geeky". My PC is VERY low-noise (less than 10db at 50cm = a person whispering in the other end of the room!) This is achieved by extensive use of watercooling in conjunction with a passive external radiator. Thus I use SpeedFan to turn on the large fan on my "Reserator" (the external radiator/reservoir) when one or more of my temperatures are high enough to warrant this. That way I only get the increased noise from this fan when I'm hardcore-gaming for prolonged periods (where the game sounds typically mask out the fan noise anyway).
If you want to make sure you get a board that have extensive support for fan-speed regulation and speed/temp monitoring, I can highly recommend Intels motherboards. Aside from typically having lots of fan-connectors as well as inputs for monitoring your PSU fan etc. They also have VERY high power-specefications for these connectors, allowing up to 25 Watt on some of them (typically the CPU fan is the highest rated one, with others being 18W and/or 10W). This will allow you to connect larger, high-performance fans and even several fans to a single output. Also, if you consider water-cooling, you will likely need the high power output to run the pump (at least I do).
Btw. I can highly recommend water-cooling (both your CPU and your GPU, possibly your RAM and chipset as well), as this is not only much more quiet (especially if you use a passive radiator) but it will also keep your hardware much cooler and it is almost impossible to overheat your hardware, even if your pump stops for extended periods (I can stop my pump for an hour without even reaching normal air-cooling temps!) Finally, water-cooling is MUCH cheaper, as all the components can be used for many years without getting filled with dust and dirt, nor will your case and hardware get covered in as much dust, due to the lower air-flow in the case.
...but do those hardware ones just increase/decrease power going thru to the fans?
