alcolix is a minimal Linux rescue distribution with the goals of being small, compatible, and very usable. It has a cozy shell and a multitude of partition rescue/editing tools, all based on up-to-date releases (e.g., 2.4.x kernel with USB support). It uses cpio.bz2 data disks and has a full GRUB bootloader, memtest86, and more.
Taprobane is a convenient GNU/Linux distribution based on Debian. It can be installed to a hard drive or used as a live CD. The philosophy of Taprobane is to bring in convenience without insulting the intelligence of the user. Its key feature is Saegiri, the configurable build system used to automate the creation of the entire ISO.