Yeah, I don't know why you'd really want FLAC on a flash player, too much space. Also, I don't know why you care when you are using it for running. When I run, I want it small w/ long battery life. I use the cheapo buds so they don't get ruined by sweat. Decent MP3's are fine at that point.

My iPod shuffle works great for this. I use the 2nd gen one. I prefer buttons so I've avoided the newest one.