The Cambridge Grammar of the English Language (CGEL), Huddleston and Pullum, 2002, a very often cited reference book in these here parts (ELL and ELU). I don't know remotely as much about CGEL as some knowledgeable contributors, and I only consult it and reference it when I need to, but it is one of the most comprehensive and coherent grammars. Note that from what I understand it is not without issues and doesn't always agree with other major grammar reference books.
CGEL is popular with many users, but McCawley 1998 is an alternative that is completely clear and well-written (by one person), with all deviations from traditional terminology explained as they occur, and no made-up terminology. It's a generative grammar, but not a Chomskyan grammar. McCawley gives top billing to the grammatical phenomena of the title, and only second billing to the theory he uses to describe them.