I've managed to improve my video by switching from the Vesa driver (enabled by default) to the Radeon driver.
The Radeon driver would not work properly without adding the line
Option '"LVDSBiosNativeMode" "FALSE"' to /etc/X11/xorg.conf. Thanks to Ricky Cambell
I also found some useful help regarding boot up speed and temperature control from this thread at the Ubuntu forum.