A lot of motherboards now have 8.1 channel surround sound at most prices and the higher the price the more the features like THX , Dolby Digital and Crative EAX.
Then you have a motherboard like this one;
Onboard Creative Soundblaster X-Fi Digital Audio Processor (20K2) with X-Fi Xtreme Fidelity and EAX AHD 5.0 Technologies
Dolby Digital Live
DTS Connect
Built-in Front Audio Headphone Amplifier
Nichicon High-end Audio Capacitors
These features are built into the motherboard and it almost makes a seperate sound card not nesscesary. There will still be some people that just like to have a seperate sound card.
What really matters is that you get something with optical output, and put good money into your receiver, speakers, and headphones. Even 'cheap' $100 mobos put out better quality audio than your average speaker system.
Also, remember that God gave you 2 ears not 7, and 2 speakers that cost the same as a 7.1 channel system will sound infinitely better. A properly set up stereo will sound just as 3D as having 100 speakers (granted it is harder to find a room that can manage it acoustically).
A good quality pair of headphones is a great option and you don't disturb anybody else if you are cranking up the volume. I used to think that you had to have a killer set of speakers to take advantage of the sound on the MB , untill I got a pair of V-Moda headphones.
Then you have a motherboard like this one;
Onboard Creative Soundblaster X-Fi Digital Audio Processor (20K2) with X-Fi Xtreme Fidelity and EAX AHD 5.0 Technologies
Dolby Digital Live
DTS Connect
Built-in Front Audio Headphone Amplifier
Nichicon High-end Audio Capacitors
These features are built into the motherboard and it almost makes a seperate sound card not nesscesary. There will still be some people that just like to have a seperate sound card.
I thought at first that motherboards had bad sound cards or like a normal 5.1 sound, but knowing most have 7.1 surround these days you don't quite need a sound card.