PC

A Pc is a excellent platform for multi media.
In case of audio, you don’t need much power for play back.

There are many different strategies to obtain best sound quality.

You can choose between a sound card or a outboard DAC

 

Probably the PC is located close to your audio. Silent operation is required.

Laptop or desktop

In general laptops make less noise but there are exceptions to this rule.
You lack the space to add a soundcard of your choice to a laptop.
You probably have to go for a outboard DAC if you want to improve on sound quality.

Storage

HDs in laptops are 2.5”,quiet but limited in capacity compared with the 3.5” models.
SSD (Solid State Disk) is the ideal choice, no moving parts at all but 1Tb in SSD is a bit expensive. OS on the SSD, music on a HD (if on a NAS, you don’t have to worry about noise) might be a affordable solution.

HTPC

There are Home Theatre PCs build with silence in mind.
Fanless PSU (power supply), heat sinks to cool the processor, silentkits for HDs, etc.

Performance

For play back you don’t need much power. Any MP3 player or cellular phone proves this point. There are claims that it is even better to go for low power.

Less electrical noise is generated and this might be beneficial for the sound quality.

FitPC	Marvell SheevaPlug

More on low power PC.

Parts

You can get all kind of parts to reduce noise level.

Big, low speed fans make less noise.

 

CPU cooler	HD silencer