Apparently the stable Linux Kernel 2.6.36 has a severe regression / bug that results in frequent (but random) crashes at the early stages of boot process. I've been experiencing this issue for around one week but considered it a problem with my setup or hardware. It turns out the problem is widespread among Arch Linux users (and others running bleeding edge distors, such as Slackware-current) and is triggered by latest udev-165-1 update. It has been discussed on the Arch Linux forums and reported in Arch Linux bugtracker and Kernel bugzilla.
For now the easiest solution is to downgrade udev to version 164-3. There are two ways to do this: using the old package from /var/cache/pacman/pkg (if you haven't cleaned your pacman cache) or downloading it from the great Arch Rollback Machine (it already saved me once!). Note: Make sure you recreate your initrd image with 'mkinitcpio -p kernel26' after reverting to older udev!