ER is a great show and I haven't watched it in such a long time! I totally think that Hollywood is shifting to more "nurse" characters but there are a lot of doctors on shows. For example, in LOST, Jack is a doctor. (haha, I keep thinking of hot guys as examples. )

I really think it depends on the character. I love Peter in Heroes and I think medical shows are centered around doctors more because they seem more interesting I guess.