I voted 25% crunch, although 10% crunch would be fine. I like a little bit of crunch to give me an idea of how the fluff ties in to the rule system, but I don't want to be constrained by it. I especially don't want a setting/source book that's nothing but crunch, which has been common in 3e. Books like Relics & Rituals: Excalibur that claim to be a sourcebook (Arthurian in this case) but have no maps, NPCs, timelines or similar, being full of feats, prestige classes and magic items, I find completely useless.