I have recently installed an extreemly useful piece of free ware called SpeedFan on my system. This programme not only displays the S.M.A.R.T. data from your hard drives as well as the temperatures throughout your system but it also gives you controll over the spped of your fans in many instances.
My PC tower is enclosed (as many are) in a specially built cupboard in my PC desk. Specially built to hide but not cool my system and I was becomming increasingly concerned that my hard drives were cooking. Especially as my previous hard drive had died probably due to this problem. I was advised about this piece of free ware but, being rahter security concious, I was a little reluctant to download it. I eventually did and it was really easy to install. I instantly had acess to the temperature data for my CPU, Motherboard, both hard drives and the ambient case temperature. The S.M.A.R.T. infor for both hard drives was also very reassuring as by checking it regularly you can tell in advance if there is any likelyhood of a hard disk failure.
The only downside was that I now knew my hard drives were cooking running at 64 degrees C when they should have been at 36. At least I was able to do something about it by adding another fan and rearranging them so thay had more space. They are still about 5 degrees too hot but much cooler than before.
If I hadn't installed SpeedFan I would have been non the wiser until one of the drives burnt out.
If I had one complaint about the produce it would be that the help file seems to assume you are totally computer jargon savvi but I would still recommend this to anyone who wants to avoid a disk failure.