Because mods aren't part of the canon game content, I thought that I'd start a separate thread from the gameplay one for Skyrim mod discussion. To begin this thread, here are PC Gamer's early top 10 mods.
You can find the current and future selection of mods at various sites, the most prominent one being Skyrim Nexus (of the Nexus Network). Planet Elder Scrolls (IGN hosted) will also feature a wide variety of mods. No doubt we'll see many sites spring up in the following months, so please feel free to post your findings.