I don't know about pointless exercise.... Internet radio is fantastic. I'm not that familar with networking receivers and would need to check online manuals to see what exactly they're capable of (inc. file formats) but as I have all my music stored in FLAC (lossless) format, the Squeezebox was the obvious choice. There is a separate forum for these sorts of devices but unfortunately on WHF, posts tend to get spread out in the computer based music forum, mp3 forum and wifi forum!
The Squeezebox/Sonos/Apple Express are all streaming devices and all have their merits. They are an audio source, in the same way that a CD player is. They connect using either analogue cables (using on board DAC) or digital cables (using receiver's DAC) and will give access to various online functions. I'm ecstatic with my Squeezebox, it supports last.fm etc. and is constantly updated so the internet radio feature is always evolving. I've listened to all sorts and the Squeezebox has transformed the way I listen to music. Since getting it, my CDP is almost redundant. As I said, my knowledge of networking receivers is limited, your best bet is to speak to someone who uses the functions and can explain how good it is. I don't think they can match a separate streaming device (remember the Xbox 360 and PS3 can also be used for streaming music but need the TV on, which is a no-no for me) but if you go down this route, do your research on the Sonos and Slimdevices sites (not familiar with Apple but know the streaming side is improving). The price difference between Sonos and Slimdevices isn't as large as it used to be but as I started with a single Squeezebox and PC running Softsqueeze (Squeezebox emulator) for a cheap n' cheerful multi-room setup, I've stuck with it and added another Squeezebox and it works fantastically well.
Visit the various manufacturer's sites and check them out.