Cool article on Improving boot time on a general Linux distribution, a good read. That said, I haven't booted my linux system for a couple of months, so in this new world of always on computing a fast(er) boot isn't nearly as important as it used to be. That said, the machines I work with at work are servers with what feels like 10 or 15 separate bios modules that take forever to start up. A boot takes in the range of 5-10 minutes, 90% of that being the system booting up the ILOM bios, SATA controller BIOS, other controllers, and then it boots up linux (which is fast enough).