XM Radio, the Deep Tracks channel (27) is where I go to hear music that I used to hear on Detroit FM radio back in the late 60’s and 70’s. There are also the Classic Vinyl and Classic Rewind channels (25 & 26) that I use as backups to Deep Tracks.
My car radio stays on Deep Tracks 95+% of the time. I have a self-seeded Deep Tracks-like Pandora channel I listen to in my home office and in my wife’s car via streaming it from my iPhone.
Had a rental car recently with XM Radio and found myself listening to Deep Tracks a lot.