Distrowatch.com, no doubt, is one of the most respectable resource for the Linux and, more generic, open source enthusiasts. This site's the most known feature is to list all possible Linux distributions available around the world. It may be your first point of contact if you are looking for the distribution of your choice.
Other than listing the distributions, Distrowatch also tracks reviews of them. DarkDuck is proud that his several reviews are listed there. Just to name a few: Ubuntu, Kubuntu, Xubuntu, Mageia, PCLinuxOS, Porteus, Dynebolic, Kongoni, Agilia, SliTaz, Crunchbang, Puppy, ROSA.
Yet another feature of Distrowatch is announcement for coming releases for Linux distributions. If you look at the list of distributions due to be released within next 3 months, which one is the most interesting for you? Which new release are you looking for most?
Please vote! The results will be announced in a couple of weeks.