Season 1: Dr. Doug Ross, Dr. Mark Greene, & Dr. Susan Lewis

Season 2: Dr. Doug Ross,Dr. Mark Greene, & Dr. Susan Lewis

Season 3: Dr. Doug Ross, Carol Hathaway, & Dr. John Carter

Season 4: Dr. Doug Ross, Dr. Mark Greene, & Dr. Kerry Weaver

Season 5: Dr. Doug Ross, Carol Hathaway, & Dr. Mark Greene

Season 6: Dr. John Carter, Dr. Mark Greene, & Dr. Luka Kovac

Season 7: Dr. Mark Greene, Dr. Abby Lockhart, & Dr. Robert Ramano

Season 8: Dr. Mark Greene, Dr. Robert Romano, & Dr. Abby Lockhart

Season 9: Dr. Susan Lewis, Dr. Robert Romano, & Dr. Kerry Weaver

Season 10: Dr. Susan Lewis, Dr. John Carter, & Dr. Abby Lockhart

Season 11: Dr. Abby Lockhart, Dr. Gregory Pratt, & Dr. Ray Barnett

Season 12: Dr. Abby Lockhart, Dr. Luka Kovac, Dr. Neela Rasgotra

I never liked Dr Ross a whole lot.
Carter, Abby,Dr Corday,Dr Romano,Dr Kovac