There are a few internet radio stations streaming in lossless flac format. Sound quality should be identical to the audio cd, but your download speed should 1.2 Mbit/s or higher (bitrate is typically between 900-1200 kbit/s). One on these stations is Absolute Radio from the UK. They’ve got also streams with music from various decades from 60s to 00s. If Ogg FLAC ~1Mb streams aren’t working at the moment try AAC+ 128k. Try also the foobar2000 music player. Additional flac stream list is available here.
Update: Absolute Radio is now only available from the UK and Absolute Radio flac, vorbis and opus streams are down. I’ve provided the highest quality aac steam links routed through some random uk proxy servers that seem to work in the foobar2000 outside the UK but without the track names.
Absolute Radio (UK) Official website - list of all streams Server status+list of working mountpoints
ČRo D-dur (classical station - Czech Republic) ČRo D-dur - flac 48 kHz Other ČRo stations - vorbis 224 kbps
EuroparadioJazz EuroparadioJazz - flac stream EuroparadioJazz - main page
Fréquence 3 Fréquence 3 - flac stream Fréquence 3 - main page
AI Radio - videogame music, demoscene, tracker AI Radio - flac stream AI Radio - main page (includes current songs's original format)