Bought a soundcard, the Creative Sound Blaster X-Fi Xtreme Audio (PCI version). The simple OEM version of 40 Euro (that's around 48 US dollars).
Used my onboard sound (VIA chip) before and also had the low volume bug. I did put in the soundcard, disabled all onboard sound stuff (both in BIOS as in Windows), installed drivers and so on. Also did set the main volume of Skyrim to 1 again in skyrimprefs.ini.
And what a difference this makes: all of a sudden I hear all kind of things in Skyrim. Normal footsteps, sound of far away rushing water, insects in the night making sounds, and so on, and so on. And most important: I can clearly hear everything that is said now
This all with normal good quality 2-way speakers.
Of course it's still a bug in Skyrim that volume is just way and way to low with onboard sound. But I am glad I did took the step to buy a separate soundcard. Did buy it mostly to see if it could solve the Skyrim sound problems but my music now also sounds a bit better, it's more "there".
I don't know it's a overall advise, but for where I am standing: when you have a bit older motherboard (I have the Asus M4A785TD-V EVO) and using onboard audio? If you can spare the money, just go for a simple (or not
) soundcard and good change you'll notice the difference 
Used my onboard sound (VIA chip) before and also had the low volume bug. I did put in the soundcard, disabled all onboard sound stuff (both in BIOS as in Windows), installed drivers and so on. Also did set the main volume of Skyrim to 1 again in skyrimprefs.ini.
And what a difference this makes: all of a sudden I hear all kind of things in Skyrim. Normal footsteps, sound of far away rushing water, insects in the night making sounds, and so on, and so on. And most important: I can clearly hear everything that is said now
This all with normal good quality 2-way speakers.Of course it's still a bug in Skyrim that volume is just way and way to low with onboard sound. But I am glad I did took the step to buy a separate soundcard. Did buy it mostly to see if it could solve the Skyrim sound problems but my music now also sounds a bit better, it's more "there".
I don't know it's a overall advise, but for where I am standing: when you have a bit older motherboard (I have the Asus M4A785TD-V EVO) and using onboard audio? If you can spare the money, just go for a simple (or not
) soundcard and good change you'll notice the difference 
I have a soundcard from the same series (Creative Sound Blaster X-Fi Xtreme Gamer) and have to say it's a purchase I've never regretted. I had used onboard audio for several years before getting it and was shocked and how much richer and full both sound effects in games and music sounded after upgrading to it. It really does make a remarkable difference.
Thanks for the proof of Bugthesda living up to its name once more OP.
My onboard should work absolutely fine though, so I'm not buying a soundcard just because Bethesda can't do their job properly.
My onboard should work absolutely fine though, so I'm not buying a soundcard just because Bethesda can't do their job properly.
Regardless of whether you think your onboard audio should work or not (and for most games I'm sure it probably does), the fact is that, without a dedicated soundcard you're not meeting Skyrim's minimum requirements of "DirectX compatible sound card".
