Here is a few:
A Quality World Map - With Roads3:11, 16 Mar 2014
SkyUI0:46, 4 Aug 2013
Lush Trees and Grass0:41, 9 Nov 2012
WATER - Water And Terrain Enhancement Redux0:41, 9 Nov 2012
Enhanced Night Skyrim0:39, 9 Nov 2012
Vals Crafting Meltdown Alpha - Melting Smelting and Fletchin1:13, 15 Jul 2012
Improved Blacksmithing
I don't use the last one, but SkyUI and the Road one are the main two that I would recommend. But with the other graphic mods it really brings out the environment.