The New Fast Boot
If you haven't seen any demos from the recent HTC press conference showcasing the company's new Fast Boot technology available on the newly announced Desire Z and Desire HD handsets, you should stop everything you're doing and watch them immediately:
The new Fast Boot allows for boot-up times as low as 5 seconds. According to HTC, Desire HD and Z
... include the new HTC Fast Boot that enables people to quickly make a call or check emails by shortening the time taken to complete the power-up sequence.