For those that want something that sounds better than Sonos but don't want to stretch to Cyrus or Naim, then consider Simple Audio:
Capable of playing 24 bit high definition tracks and supporting most audio file types, it really does sound excellent. Multiple units can be set up to allow music around the home.
Connection is via in-built ethernet over mains. Two versions are available. either with or without an internal amplifier. Prices are £599 and £499 respectively.