I have recently been playing around with using Raspberry Pi devices as streaming music players within a Squeezebox-based system. I've arrived at quite a comprehensive arrangement, which includes a Pi as a player:
This is a rough illustration of my current implementation of a network of Squeezebox players linked to a NAS (GrumpyBox) running Logitech Media Server (LMS). It consists of several Logitech Squeezeboxes, a couple of iPads that are playback-capable through apps such as SqueezePad and iPeng, and the software Squeezebox emulater, SqueezePlay. To this I have recently added a Raspberry Pi running piCorePlayer. I also have a second Raspberry Pi running Squeezeplug, which has its own instance of LMS (not shown in the diagram).
I've summarised the usage cases of the three setups I have tried in the table below. My opinion can be summarised as:
If all you want to do is run a media player connected to an existing LMS, choose the piCorePlayer option.
If you need to set up a media server as well as a player, choose the Squeezeplug option.
By far the most versatile of the two DAC cards I've tried is the Wolfson DAC - if you want to use this, then Squeezeplug or the custom Wolfson kernel options are best.
Both Squeezeplug and piCorePlayer work well with USB DACs
I set up a script for a button press to shutdown the Squeezeplug (and the Wolfson kernel) systems so the Pi can be safely powered down. See here.
For both the Raspberry Pi based devices I use, you do need to think about how you interact with them. I use the LMS web interface (usually found at http://IPaddress:9000) with a laptop, or one of the many tablet or smartphone apps that are available (such as the afore-mentioned SqueezePad and iPeng).
Installing any of these devices is much easier if you have a reasonable amount of experience with the Linux command line. On the other hand, a Raspberry Pi is a pretty good way to learn the Linux command line!