I only found Wizardawn recently, through a link on someone else’s blog (Maybe Troll & Flame? or from someone on his blogroll? It was late last night and I forget).
This has to be the most useful site ever, with tools for generating towns, dungeons, wilderness, and so on. So far my favorite feature is that it generates numbered maps from various geomorphs. The ruined cities, village, and town maps look awesome, and the dungeon geomorphs will be familiar to users of other online random dungeon generators.
Many of the encounter tables for the tools use Labyrinth Lord or OSRIC, but things are pretty system-neutral. If that weren’t enough, you can download a number of interesting sci-fi and fantasy games — RPGs and board games — created by the anonymous owner of the site. For free. Check it out.
Also, many thanks to the creator of Wizardawn, whoever you are!