Arch Linux (or Arch) is a great Linux distribution intended to be lightweight and simple. The design approach of the development team focuses on simplicity, elegance, code correctness and minimalism.
It is binary-based, unlike source-based distros (see gentoo, which is used by l33t hax0rs who think that compiling everything for a 1% performance gain is worth their time).
It is loved among knowledgeable linux users for features such as the 'pacman' package manager and the AUR (Arch User-Community Repository) which contains PKGBUILD scripts which simplify building packages not in the main repositories from source.
Arch User: What's up, gentoo user? I just finished installing Arch Linux, it took about 20 minutes.
Gentoo User: I'm just recompiling my kernel for an estimated 1% performance increase on this AMD K6. I expect it to be done in about 2 weeks. I can't wait!