Steven Sinofsky posted another update on Windows 8, this time about the boot time

Qualitatively, people say they prefer to shut down because they want to have their PC completely “off” so that it uses no power – either to preserve battery life or to reduce their energy use. Hibernate is also a good option for this since it similarly has no power draw, and many people really like it. However, it’s clearly not for everyone, since one of the other things we’ve heard is that many people want to turn their PCs on and have it be a “fresh start” rather than running all of the stuff from their previous session. Sleep/resume is the best option for fast on/off transitions on today’s PCs, but it still consumes some power in order to preserve the contents of RAM, which means battery drain – even if it’s only a little bit on a well optimized system. All of this is happening with the backdrop of how we all use our mobile phones today, which is almost never restarting them, and always using what feels closest to a sleep-like state.

  Delivering fast boot times in Windows 8