Well, the idea of guild points to purchase things certainly sounds interesting! It'll probably be enough to motivate me to join, and I hadn't originally been planning on participating in guilds when I first saw the idea, but the incentive should bring me around
I don't know what kinds of things you had in mind for purchasing with guild points, but I suppose the standard reward codes would be possibilities, as well as things like upgrade or rare cards, or things like foil art cards, or even things like pimped out playmats or getting to use mark images from the hybrid mark thread or that sort of thing. In terms of purely forum-based things, there's always stuff like buying increased PM space, larger signatures, and the like. (I know I'd like to have a larger signature... :p)
And yeah, as Marsu asked, I'd be interested in knowing how the guilds will be structured. Will there be 12, one for each element, or will anyone who wants be able to create a guild, or something else?
edit: Oh, and maybe extra oracle spins could be bought, too
I like when the fat man gives me pretty women.