Oooh, I might have to check out that WKHR! I get WAHS over the air here, it's likewise a high school with a bunch of music programs throughout the day. No screaming ads, just the occasional PSA, and the DJs genuinely care about the music. It's a breath of fresh air.
WWOZ - New Orleans gold mine, especially 2 week audio archive
KCRW - live + curated streams
Cultura Brasil - a curated, updated stream of Brazilian music
BR Heimat - odd, but I find corny alpine brass bands a great working soundtrack
WKHR - a high school radio station in Cleveland where old people play 78rpm records