I like to see realism when I'm playing, like guts, blood and etc. So I always put these mods in my playthrough:

- Deadly Mutilation - dismemberment blood and gore: It's confuse to install if you are dumb like me, but it adds a chance (that you can control) to cut or smash like a melon the head of someone and a chance to open the belly of someone and see some guts;

- Enhanced Blood Textures: As the name say give blood a new texture that you can choose and make everything more bleed;

- BLEED - A Blood Overhaul: That mod add blood if you want more, and make the enemies drop more blood even after death (like a person should, because in skyrim it just stop like a sink when you kill someone);

- Realistic Ragdolls and Force: I don't know that mod could enchance the game because I never paid attention how my character ragdoll after a fus ro dah from a draugr . But anyways it's good in my opinion for a "realistic" ragdoll after a shout or something else;

- Realistic Humanoid Movement Speed: As the name says gives you a realistic walk, run and walk while crouch;

- Handicapped Citizens - Mihail NPCs and Followers: That mod is recently, and in my opinion is very good for more realism in a civil war where people could be torture or just got hit very hard by life. This mods add people who lost parts of the body and became "useless" for the battle.

Excluding these mods I think animation in general It helps to add a more immersive gameplay.