Regarding the title..
The variable that is changing is the desktop environment. The primary measures that were taken were power and performance. The test was consistent.
I guess the title could have been "Power and Memory Usage with bundled GNOME/KDE/LXDE/XFCE on Ubuntu Karmic while running Video" - but I think that would just look silly.
Title could be "Power & Memory Usage of GNOME/KDE/LXDE/XFCE on Ubuntu" and it wouldnt be silly at all. Actually it would be _correct_.