This is the INI I have been using for Realistic Lighting 3.31 by Pluto, 747823, and Leviathan1753. My goal was to have days be more colorful, with deep blue skies and vibrant colors, and for nights, interiors, and dungeons be bright enough to actually play the game.

I cobbled this together using other INIs available here (Sydney, Pete117, Psychosteve) and then made several tweaks to try and get something happening. The end result is some pretty nice days, followed by some genuinely weird crap happening on cloudy nights or rainy days. Far from perfect, but I think the good outweighs the bad. Maybe you're the kind of person who didn't write a 23 page manifesto to Blizzard after they posted a screenshot of Diablo 3 that had colors besides red and black in it and like some color in your game. If so, you might want to give this a shot.

There's a laundry list of issues, like the mountains appearing as white shapes on rainy days, and weird night lighting, some overly bright interiors (Dragonsreach in particular). What I as going for was a more colorful, fantasy-like lighting setup and Realistic Lighting was not really authored towards that end. The base mod prefers darker darknesses, which I am not a fan of, so to make things look good in one instance, another instance pays the price. Still, the daytime looks awesome.

The only other mod I am using that affects lighting is the famous Shadow Striping Fix by Miral. No ENB, FXAA, post processing blibbedy flibbet or anything.

Special note: Riften looks like crap. I have no idea how to fix it.

Other mods in use in the screenshots that affect overall appearance:

Skyrim Sunglare V3 by Laast (with Lensflare)
Realistic Water Textures and Terrain by isoku
Skyrim HD - 2K Textures by NebuLa (Lite Version)

Several screenshots included, peruse at your pleasure.

Thanks and credit go to:
Pluto, 747823, and Leviathan1753 for the Realistic Lighting mod
Sydney666, Pete117, and PsychoSteve for providing their INIs for inspiration.