I'm not an Arch user. In fact, I've never used Arch before (save for two reviews of Chakra GNU/Linux, an Arch-based KDE distribution made to make Arch easier). So why am I talking about the Arch Wiki?
Well, I'm looking into doing a couple more respins, and the Arch Wiki has been absolutely indispensable for configuration tips. As Arch Linux is built from the ground up, there needs to be thorough and up-to-date documentation about how exactly to install and configure various applications and services, and the Arch Wiki does not fail. Everything is laid out in a way that I can understand, and the presumed level of prior knowledge is quite low, which is nice. Plus, because Arch is meant to be fully customizable, there are many alternative tools discussed as well, even if they aren't as frequently used.
So thank you Arch Wiki for helping me do these respins! (Also, stay tuned for posts about these new respins!)