For extra immersion, I highly recommend the
Sounds of Skyrim mods.
There's currently 2 mods released,
Dungeons and
Wilds, with two more coming (
Civilization,
Special Events).
SoS - Dungeons:
http://skyrim.nexusmods.com/downloads/file.php?id=8601
SoS - Wilds:
http://skyrim.nexusmods.com/downloads/file.php?id=10886
And the previews,
,
and
.
