Ubuntu 10.10 has only entered the Beta. However, it looks like it is doing extremely well in cutting down the boot time.
James Ward posted a video showing Ubuntu 10.10 in a mere 8.6 seconds. That is the total time it takes from GRUB to get to a usable desktop. According to Ward, he did not do anything special, like disable the drivers etc., to reduce the boot time. But of course, he uses a SSD.
Makes me want to get a SSD for my computer before Maverick final release.
If you cannot see the embedded video, click here.