Krug
Newshound
Do you think some d20 books have become 'definitive'? For example, Mutants and Masterminds appears to have become the definitive supplement for d20 Superhero RPGs, while Call of Cthulhu is the definitive horror supplement. (Whether you use it for horror or not)
What other books would you classify as definitive, if any?
What other books would you classify as definitive, if any?