This.
I didn't think it was dark enough, but then I never thought that Oblivion was either.
I use RL and have been for a while and it is truly awesome even just on it's own.
I do use an ENB as well, mind...

Turn off any sort of dynamic lighting. That really svcks the vividness out of the game.

To me, dark isn't dark enough. Night doesn't feel like night and the dungeons are too well lit for no light sources.

The game settings are "debatable" at default and have to be adjusted to your tastes- but a display/tv needs to be calibrated properly before on the basis of the contents/environment and with at least two profiles (day/night) you can find free patterns on the net for that purpose - if a professional calibrations isn't possible - but do only the basic regulations like contrast,brightness etc.on your own.

And a suggestion more to others: don't "generalize" on the plasma "blacks" etc. because there are several of them that have even poor blacks in 2012.

As you can see by reading this thread so far, there is an endless discussion on whether dark areas and nights in Skyrim are too dark or dark enough.
I play on an IPS monitor, and since I also use it for desktop publishing and web design, I have it carefully calibrated with professional software. Having said that, I seldom need to use torches, spells or other kinds of supplementary lighting when at night or in dark interiors in Skyrim. In fact, I even lowered the gamma in-game a little bit because everything felt too bright!

If you browse the Skyrim Nexus, you will be surprised to see how many mods actually implement "darker nights and interiors", including most FXAA Injector and ENB-based mods. Finding mods that make nights and interiors brighter is much harder. That should tell you something about the default lighting in Skyrim.

I would humbly suggest that you check the "dynamic contrast" setting in your plasma HDTV. Most TVs today use dynamic contrast ratio by default, which makes TV shows and movies look better, and of course, makes the image look awesome when you look at the TV in the store. Some TVs also have a "gaming" preset, which reduces the dynamic contrast, as well as much of the post-processing (which can also introduce input lag).

If that doesn't work out for you, get back to us and we will, hopefully, continue in helping you to find a solution.

I too found the lighting to be what I would call "stark" at first and could not seem to fix it with in-game settings. Then I turned to the TV settings. The "Gaming" setting on my Samsung HDTV made the lighting look more even but washed out the colors. So then I went into the color, brightness, contrast settings and fiddled until I had a nice, even, colorful display (to my eyes).

I think there are two issues here. The display settings and the game's ambient light. I think if you can get the display settings to look right to your eyes, then you can tackle the game's ambient light if you're on the PC and so inclined.

I just thought this might help.