Well, I'd divide this into two different textures of crunchy. There's the point-buy crunchy rules and the heavy-mechanics crunchy rules. For point-buy crunchy it's GURPS and Mutants & Masterminds. Both these RPGs are very well done, but I really get lost in them. So many things you might spend points on, varying effects for levels of each power, and millions of possible combinations. OMG. I'm only okay with point-buy (Wait, why do I keep typing "pint-buy"? Am I thirsty?) but only if it's not too deep. I like BESM, for instance.
For heavy-mechanics crunchy rules I'd say Chivalry & Sorcery and D&D 3E/Pathfinder. C&S was very crunchy--more crunchy that it needed to be. D&D 3E/Pathfinder is also crunchy but because of the mass of material rather than the base mechanic: just roll 1d20, but then review the 487,264 possible modifiers. Dang.