Re: IDX registration
The way we typically advise you set up your registration is the way you see it on the majority of our IDX's - why? Because that is what our clients have told us work the best (And many have tried all sorts of registration) i think it works well because users are already committed, they have filled out the search, and likely viewed several "listings" views or pages of listings before they finally see one that they want details on, so being prompted to register (And outlining the features and benefits to register, not make them feel like they are going to be spammed) always helps.
Starting LEC 7 soon but it won't be called LEC 7 - LEC 2012 coming soon!