I prefer the fireflies to the rain, so I have the rain off.
The trickling waterfall was making me want to urinate almost as much as the fountains in the 'hoods.
Oh and turned the sticks and stones off because I didn't like their face! So THERE.
The real test of Relto customization will come from pages that perhaps are mutually exclusive or pages that combine. Or when we start to have pages that run along certain themes, like plant-themed pages, or wildlife, or flying creatures, or Myst-derived additions like the dock and the tree. Or pages that are significant to one IC group or another.
And along the same lines as the fireflies, maybe there'll be objects we can link with to Relto, so we can get things we wouldn't be able to get through the pages, allowing us to further customize.
For the first year of Live at least, I don't see Reltos diverging too much from the way they look right now... that's a conservative estimate from someone who isn't working at Cyan, and not based on anything other than gut feeling... but Relto is meant to be indicative of the player's attitudes and preferences, rather than being increasingly different from each other. In fact I'm willing to bet that having all the Relto pages turned on is a good indication of a greedy explorer.