I've seen this meme a lot lately, and frankly I'm not impressed.
Limiting the selection to a "top ten" seems hardly strict enough. Seems like the easy way out.
Instead, I want you to give me a "top three."
1. Labyrinth Lord. The best version of the best version of D&D.
2. Fudge 10th Anniversary Edition. The most flexible and intuitive RPG ever designed, in my experience. I'd use this for everything and anything that D&D didn't do better.
3. Delta Green (Call of Cthulhu). Even without any version of the CoC rules to back it up, this the single most exceptional example of an RPG support product to appear in the last two decades. Indispensable.
Book: Office Space - *Murder Must Advertise* by Dorothy L. Sayers. HarperPaperbacks 1993, Originally Published 1933 This was the edition I read. Can't say I like the cover, but ...
4 hours ago