I'll give you my essentials list :)
Skyrim Redone. It alters pretty much every part of the game in some way, rebalancing and adding new content. It's just a superior game to vanilla, and still feels like a finished Skyrim, not a mod.
Monster Mod/Wars. This is two mods. There are Lore Friendly versions if you don't want out of place monsters, but they add SO many new spawns. Just walking down the road, boom, fire breathing Gargoyle.
Realistic Ragdoll and Forces. This just changes the ragdolls so they don't look inflatable. Looks closer to something out of source engine.
Crimson Tide. Much better blood effects.
Immersive Armors/Weapons. These two can be added to SkyRe. Just adds a whole bunch of Lore Friendly armors and weapons to the leveled lists.
Deadly Combat. This one might be a bit tricky to make work with SkyRe. I don't know how familiar you are with mods, but basically you install SkyRe without it's Combat and AI Modules, then you put the Deadly Combat Module last in the load order. This one is ESSENTIAL. It changes the entire flow of the game, for the better. Fights become tactical and damned fun. An epic level player being jumped and surrounded by 10 low level Bandits can actually die if you don't play smart.
Deadly Dragons. Another with Lore Friendly versions. Just adds some new Dragon types. I've found a few that were actually a solid challenge, like one that sends a fog to blind you and then harasses you with a rain of fireballs.
Duel Wield Parrying. Lets you block with your hands full! I'd suggest getting a gamer mouse for this one, as you need to map a new block button, and I've found a side mouse button works best. So now Battlemages and duel sword users can actually block. Works great with Deadly Combat.
I have more, but they're not nearly as important. All cosmetic things like Proper Length Arrows. Which is still awesome because it makes arrows punch right through the other end of a body.