The only show I can think of off the top of my head that does casting well is Gray's Anatomy. Races, genders, ages, sexual identities—you name it, it's all mixed in at all levels from surgeon on down. And it's an ensemble "soap opera," so it's not just one or two faces up front plus the sidekicks. Hospital soap opera isn't really my kind of show, so I haven't watched a lot of it, but I wish everyone was casting this way. Other than a slightly higher proportion of "Hollywood beautiful" faces, it looks like walking into the hospital down the street from me.