Well, a story that naturally hits me now is the change by Apple to the processor fan's response threshold - something was changed with 10.3.3 and since then, the fan is basically always on in a 12" PowerBook (at least in the older ones - mine is still one with 867MHz). Annoying, that. Before, it was a nice quiet device, now it's noisy - especially when operating on the power grid. And this even when there is absolutely no activity on the box (MenuMeters shows absolutely low-level activity).
There used to be a software called Silent Night, which replaced two kernel extensions (AppleADM103x.kext and AppleADT746x.kext) with older versions and thus reset this control to old values (which, after all, did work). There is also a description of this available. But somehow, you can't find anything there anymore - the links are dead. Does anyone have a useful idea of what could be done? The 12" PowerBook unfortunately doesn't have the processor setting "automatic" (for some reason), but only "maximum" and "minimum" - and a castrated processor wouldn't be any better than a noisy fan. If it were automatically regulated, it would be okay, but as it is ...
Somehow, I find it pathetic that Apple doesn't offer a usable solution. Simply imposing fan noise on the user is quite harsh - especially since I couldn't find any documentation about it at Apple. Normally, you would at least expect a knowledge base article on this ...