I'm a big fan of Lubuntu (Light Ubuntu), the Ubuntu without all bloated software since, on average, it saves up to 1 or 1.5 Gigas or RAM when compared to standard Ubuntu will of the fancy (and useless) 3D effects.
Something that annoys me anyway is that the default setup in Lubuntu (I ignore if that's the case in Ubuntu) is quite energy-hungry.
I use a Dell XPS 13 laptop equiped with brand new hardware that "theoretically" must work in silence most of the time, but when I just boot up Lubuntu and a couple of apps (Firefox, Eclipse) the fan starts to run at max speed.
The easy (patch) solution is to run next command:
then go to the "Tunables" tab, and switch all from "Bad" to "Good", except most probably for the USB keyboard and mouse and the wifi or ethernet. (For those really concerned with the integrity of their HD data, don't swith also al SATA related stuff).
Actually, activating the power saving for the PCI Intel Core processor Graphics Controller is usually "good enough" to make the fan settle down, but switching on all the others makes no harm and our computer will be happier with us (don't forget that sooner than later IA equiped macro-computers will punish those poor humans that through the years tortured their indefense CPUs, so it's better to get friends as soon as possible before it's too late).