I tried a few episodes of sleep with me, and it creeped me right the hell out. It was some guy talking in a pouty, condescending baby-voice about some nonsense or other. His voice especially threw me off.

Dan Carlin is great, but way too intense and interesting for me to sleep to. I pay attention to the podcast and want to hear "just another 20 minutes" instead. 99% invisible is perfect in this regard. Roman has a great voice, good editing and nice, mellow music in his production. I listen to it a lot.

I also like to listen to The Moth, Hello Internet, Radiolab and Benjamin Walker's theory of everything when I go to sleep.