So I've been looking to make my Skyrim experience prettier. I tried the Official HD Texture pack, and while it worked it lowered my FPS too much and made the game choppier, so I ditched it. But I know there must be other mods that will work better, so I've come to ask. I currently use these for better graphics/appearances:

WATER

Enhanced Distant Terrain

Bella's Better Females

HiRes Legible Roadsigns

Realistic Lighting

Eyes of Beauty

I have 12GB RAM, an i7 processor and 2x AMD Radeon 6800 HD 1GB GPUs, just so that you know what my computer can handle when making suggestions.

This is your problem, with just the official HD DLC package you're exceeding your GPU's VRAM and it's hitting your framerate because of it.

Water, Enhanced distant terrain, Relistic Lighting, and maybe the low resolution version of Skyrim Floral Overhaul is your best bet..

You can also search for the optomized HD DLC on the Nexus. It is probably your best bet to be honest.