The latest Ubuntu 9.10 alpha release includes significant improvements to boot performance. Tests show that the popular Linux distribution can now boot in mere seconds on a computer with a solid state drive. More here
I installed Ubuntu 9.10 alpha 6 on a Dell Inspiron 1420n, the Ubuntu laptop that I reviewed in 2007. I conducted extensive startup performance testing and used the bootchart utility to measure the results. My average boot time was 22 seconds, with Xorg starting roughly 13 seconds into the boot process.