I think what's most impressive about this show is not only how good the writing for the main characters is, but how good the supporting characters are. I can't think of a character that isn't hilarious: Todd, Doug, Ted, Randall (aka Crotch Punching Midget), Snoop Dogg Intern...
I remember an amazing moment from last season when Kelso was proving the JD that Cox disagrees with everything he says just for the sake of disagreeing:
Kelso: It's hot as hell around here.
Cox: Freezing.
Kelso: The coffee is delicious today.
Cox: Rat piss.
Kelso: Dr Murphy is an incompetent suck up.
Cox: Actually Bob, Dr Murphy is one of the most talented young doctors I've ever had the priveledge to work with.
*They both walk off, leaving the interns behind. JD turns to see an exuberant Doug holding the phone.*
JD: What are you doing?
Doug: I'm calling my dad!
Gold, I tells ya.
****SPOILERS****
For those who dug Tom Cavenaugh as JD's brother, he'll be back on the show in October. Julianna Margulies will appear as an attorney in an upcoming episode.
****SPOILERS****