Playing web radio is an important requirement. A goal is to replace terrestrial radio with web streams of terrestrial radio, but I imagine it will be tough to use a network music player to navigate to that content.
Dedicated internet radio devices exist, and manage the navigation rather smoothly.
The
Sanyo unit we got for SWMBO's mom this year, was cheap-ish (C$170), has 802.11g and
wired ethernet, sound in/out jacks, built-in speakers,
no wall wart, lousy monchrome display, and a horrid UI.
But even with that (incredibly) horrid UI, it's still easy to navigate and "tune in" the planet. We left her with a bunch of classical stations pre-tuned on the preset buttons.

This device became a necessity because a local Hamilton pop radio station, 0.2 on the dial away from her favourite WNED-FM, recently doubled power and now overwhelms it's more sedate band neighbour. Internet radio seems the only way to get it now, other than via expensive digital cableTV.
Cheers