You do not need to put a high-end sound card into a computer to get really solid sound out. All you need is a USB cable and a digital to analog converter (a DAC) or an audio device that includes one. These are not hard to find and run the gamut from surprisingly cheap to outrageously expensive.
I usually end up somewhere in the middle on these things.
In my study, where I spend a lot of time, I feed the USB output of my computer to a Music Hall digital to analog converter. The Music Hall DAC also has a digital optical input connected to a Sonos player.
The Sonos system is marvelous. I've got mine connected to a music collection stored on a networked file server. I alternate between music fed by my computer or coming from the Sonos system by selecting which input on the DAC I need. The DAC converts the digitized music into good old fashioned analog sound waves, either driving some headphones or a set of DynAudio speakers including a modest subwoofer.
I have placed Sonos devices throughout my house so that the music accessible to me in my study can be played anywhere I want. The Sonos devices connect to each other through their own wireless network. The setup is really simple.
I use a pair of Sonos speakers in my basement to create a no frills sound system. I use more elaborate gear with a different DAC to feed one of the inputs to my traditional stereo system. The gear is very flexible.
The Sonos devices are controlled from a computer or with an app on your tablet or smart phone.
And it all starts with a simple USB output from a computer and little else . . .