Skyrim's a beautiful game. I've said it before and I'll say it again. That doesn't mean we can't make it look even better. Thanks to the efforts of modders, we can do just that.
One such mod I'd like to cast the spotlight on is Realistic Colors and Real Nights by an Italian modder who goes by "aLaaa." It's now up to version 1.4. There are other aesthetic mods, but I like this one the most because of its creator's insistence on bringing a good bit of realism to Skyrim's environments.
Instead of making the game look like a high contrast nightmare or a Disney cartoon, the mod is an attempt to introduce a real HDR engine to Skyrim. Using a "doublepass" system render, the mod offers better reflections and brighter (but not blindingly so) days. Based on cold sepia effects and low color saturation (like what you'd see in a photograph taken in Norway), the mod reflects Skyrim's location in the northern reaches of Tamriel. You can see the result for yourself in the few images I've attached to this post here.
Even better, the Realistic Colors and Real Nights mod also includes the latest version of Realistic Water Textures.
Skyrim has never looked so good.