For option-heavy games like Pathfinder or 4e, I'm increasingly convinced that the way forward is some sort of online database (be it PFSRD or the DDI Compendium). Once the number of books grows, finding the specific item you want somewhere in those thousands of pages of text becomes problematic.
That said, actually building that online database (and, in particular, monetising it) is rather more tricky - especially as the market still seems wedded to the notion of having one or more big, bulky core rulebooks for the game.
