I saw this comment on the Windfarm thread and it touched a nerve...
"The vast majority leave their PCs on overnight as it takes so long to start them up next day."
How bl00dy true is that! My company has a policy of switching off PC's overnight, but few people do because:
1. MS Windows takes ages to boot
2. You lose your context (we are mostly programmers)
But laptop BIOS's have supported "Hibernate" modes and servers have "Wake on LAN" and it's about time desktop PCs did the same. I reckon the overall energy savings would be significant.