I love Xen. However, I also see some UI concepts, where I think, why not go all out modern like with the overlays and ajax too? Not so much to overload, but where it makes sense. Kier will probably slap me for this thread and I bet he probably knows or will want to do this kind of stuff already , but here goes anyway.
Why have separate and sort of dislocated pages for the user to change things on their profile page?
Don't slap me Kier! Hope I could help!