So I found my old stopwatch and decided to time the boot lengths of several different LiveCDs. Here are some results for two different computers.
All LiveCDs were burned using the same options, on the same burner, onto the same media, from the same spindle (except for the SUSE LiveDVD). The slower computer is a 333 MHz AMD K6 laptop with 64MB of ram, no hard drive, and no networking of any kind. The faster computer is a homebuilt AMD Athlon64 3200+ with 1 GB memory, and for the tests I turned off the hard drive and built-in networking in the bios. I started timing from when I hit "enter" from the initial menus from the LiveCD boot process, and stopped when the CD activity stopped. Also, I stopped timing while the LiveCDs were prompting me for information.
Results so far:
Slow Laptop (AMD K6 333 Mhz, 64 MB memory):
SLAX 5.05: 1:18s to command line login, 2:35s total (into Fluxbox), I let it go for 10.5 hours before stopping the KDE boot
Damn Small Linux 1.0.1: 1:19s total (Fluxbox)
PCLinuxOS p81A: crashes immediately
Ubuntu 5.04: I stopped the process after six and a half hours
Knoppix 3.8.1: 2:43s to TWM (it check for memory and swap space and switches from KDE automatically)
Kanotix 2005-02: crashes when searching for partitions
SimplyMEPIS 3.3: 11:20s to KDE login, it was not able to finish before I had to shut it down
Gentoo 2005.0: 2:58s to command line login
GoblinX 1.1: crashes
Desktop (AMD Athlon64 3200+, 1024 MB memory)
SLAX 5.05: 0:36s to command line login, 0:58s to Fluxbox, 1:29s to KDE
Damn Small Linux 1.0.1: crashes when starting X
PCLinuxOS p81A: 1:35s to KDE login, 2:22s total
Ubuntu 5.04: 3:41s total
Knoppix 3.8.1: 2:08s total
Kanotix 2005-02: 2:16s total
SimplyMEPIS 3.3: 2:15s to KDE login, 4:10s total
Gentoo 2005.0: 1:07s to command line (no login)
GoblinX 1.1: 56s to cli login, 1:48 to KDE