19. Which RPG features the best writing?
I don't really look to RPGs for elegant writing, the same way I look to literature, and I'm often put off by games that insist on including fiction with their text.
What I really want in a game book is clear, concise prose that helps me understand the game and gives me the ideas and tools I need to run great games. For that, I don't think you can beat Avery Alder's MONSTERHEARTS (and MONSTERHEARTS 2, the recent update).
It was MH that helped me really get my head around the "Apocalypse Engine". I could easily call Vincent Baker's original AW text "the most provocative RPG writing", but I didn't really understand the game until Avery explained it to me. And the revised game is all killer, no filler. If you haven't got it already, what the heck is wrong with you?
20. What is the best source for out-of-print RPGs?
I don't think there is any substitute for the serendipitous pleasure of stumbling across a game book long-sought but out-of-reach on the shelves of an obscure second-hand book store.
PDFs make a lot of the old stuff accessible, of course, and you can occasionally find a deal in the dusty depths of eBay or at a garage sale, but used book stores (and bins of second-hand games at your FLGS) are where it's at.
21. Which RPG does the most with the least words?
Hmm, I don't read a lot of micro games, but Graham Walmsley's CTHULHU DARK is pretty awesome stuff.