Stone, there are a number of texture mods on Skyrim Nexxus that take care of creating that sort of realistic scenery quite nicely, and with every opportunity to not kill frame rate.
I'm running about 10 different scenery enhancement mods - two of which adjust the lighting/saturation/etc. and the others which add HD textures to buildings, ground, rocks, water, sky, and animal coats. There are so many you can run. I've also redone my character with hair and face mods. Turns it into a brand new game.
You could go with just the Skyrim 2K texture mod (I use the lite version with my GTX460 and see no real difference vs. the 'Full' mod except frame rate and it's light years better than stock), and get away with it, but if I were you I'd go to Skyrim Nexus website, type in "Skyrim Total Enhancement Project" in the search box at top right, and download and read the PDF that comes with it. By the time you go through that, your Skyrim will look like the pics above, or mine below, even though they are in a different (less foresty areas).
You should be able to see the difference in textures. Tree and plant density and lushness, ground texture detail, weapon and armor re-textures (runes on the Daedric bow and designs on axe heads, plus Nightingale Prime do over), skies, level of detail on wood and brick for buildings, rocks, plus of course the hair, face, eyes, and lips in the photos. Even the deer jumping in the back on pic 4 has a fuller more detailed coat. I'll post others of the awesome water, smoke and mist looks when I get back up in the hills.