The Special Edition trailer focuses on trees, so I'd recommend the Skyrim Flora Overhaul, which provides new textures, lusher colors, better trees and bark, lovelier plants, and taller grass.

The dedicated Simonrim team has released a Skyrim survival mod that makes the vanilla survival experience much better across all of Tamriel.

A new patch for Skyrim makes the game run worse, not better. Bethesda distributed a patch via Steam last night for PC owners of the game with very little fanfare.