I just thought I would throw this one out there.

"WattOS, as its name suggests, is focused on low power usage and having a small footprint – allowing it to run on older, less powerful hardware. Makes new machines screaming fast also"

http://www.planetwatt.com/

Would this be useful with laptop computers?

Looks like one could do the same with any Linux distro just by turning off (or not installing) a lot of services.

Indeed I prefer to start with a minimal Debian/Ubuntu installation and then add the packages I need. It`s a pain in the beginning but once you`ve figured out the dependencies you`ll probably end up with something lighter than all those "lightweight" distros.

Another thing I`ve noticed is that LXDE which is often the prefered lightwqeight DE, is more cpu intensive than XFCE and even Gnome. XFCE takes a bit more memory but is consistently more responsive when minimizing/maximizing/moving windows on a PIII @ 833mhz.

I don't see why not, its based on ubuntu and aimed at minimising/saving power.

I always meant to start getting into Linux. Maybe I'll just put this on my laptop after the exams are over and fiddle with it throughout the summer.

I am very sceptical of linux distros created for specific purpose. Espessially ones that are ubuntu spinoffs
The main big distros can usually be modified to same goal too.

laptop-mode is a great package available to most distributions. It is all-in-one power saving center.
And then add powertop to monitor your CPU power state and tweak whatever causes for wakeup from idle.

I use Arch linux myself. Fastest package updates and can be modified to your goal without compiling/tweaking everything manually

Finally someone has published a review of wattOS and it doesn't look too good. According to the guys at Phoronix

Low power Linux(wattos) is based on Ubuntu 10.04..it works good with older and less powerful hardware.
Even if you are non-technical but still you will be okay with the way the desktop works if you used full-fat Ubuntu before.