Yesterday M.P. asked a question - what are your most inspirational rpg products? It's my attempt to answer this question. It will be rather short list as the most of my inspirations do not come from RPG stuff.
Castle Drachenfels - probably the last module-like adventure for Warhammer FRP. Sick, lethal and full of great ideas (animated dinosaur skeletons!). I was 14 when I grabbed it and it was something I needed. Too bad that I don't own it anymore :-(
Disciples of the Dark Gods - Dark Heresy sourcebook. I grabbed it as soon as it was released. It's almost overloaded with ideas of evil cults, blasphemous artifacts, sorcery etc etc etc.
Dreamlands - need I say more?