Mandriva is an RPM-based Linux distribtion. It excels at usability and simplicity, features thoroughly preconfigured KDE and GNOME desktops, and includes cool tools like supermount (transparent access to removable media) and DiskDrake (a full-featured graphical hard-drive partitioner). Unlike former versions, Mandriva is not a tuned-up Red Hat, but a very mature Linux distribution on its own. Mandriva is published by a company, but is a completely open and transparent free-software project.
Gentoo Linux is a versatile and fast Linux distribution for x86, PowerPC, Sparc, and Sparc64 that's geared towards Linux power users. Unlike other distros, it has an advanced package management system called Portage. Portage is a true ports system in the tradition of BSD ports, but is Python-based and sports a number of advanced features including dependencies, fine-grained package management, "fake" (OpenBSD-style) installs, path sandboxing, safe unmerging, system profiles, virtual packages, config file management, and more.