*shrug* If you see a benefit to keeping your CPU at maximum speed all the time, then go for it. For myself, I really don't see any difference in "snappiness"...if you were to set my system one way or the other and then ask me to guess which it was based on some general use, I doubt I'd be able to do any better than pure chance. So I don't see any advantage to keeping my processor at full speed all the time; might as well save the energy and make things a little easier on my air conditioning in the summer.
Also, I don't see the relevance of the "two year" figure that keeps coming up in this thread. To me, a two-year-old computer is still basically "new", not at the end of its life. I'll be damned if I let the tech industry force me to upgrade frequently, to the benefit of their profits, when what I already have is perfectly capable of meeting my needs. I don't like the cycle that these companies create, where "progress" means that you need to buy new software periodically just to do the exact same thing that your old software was already doing, but to use the new software, you need new hardware, which then has difficulty running your other old software, so you have to upgrade that software as well...all when, if others had just left things alone, you wouldn't have had any reason to spend a cent.