These days almost everything works out of the box on most hardware. Linux autodetects almost every piece of hardware and loads the modules. For someone who is used on running Linux on outdated hardware even Debian provides all that is needed...
...that's what I've been experiencing until I came across an ASUS P4P800 board with an Intel ICH5 (AC97) chipset. It's listed as:
00:1f.5 Multimedia audio controller: Intel Corporation 82801EB/ER (ICH5/ICH5R) AC'97 Audio Controller (rev 02)
Everything looked ok, but no sound could be heard. After trying out every connector and fiddling with the mixer settings a lot, still no sound was heard.
The internet and the ALSA-Configuration.txt from the Documentation section of the linux kernel provided me with some hints to set some options for the snd-intel8x0 module. Sound was enabled with the following options line:
options snd-intel8x0 ac97_clock=0 ac97_quirk=inv_eapd