David Tennant marvelously prove himself up to the task of follow Christopher Ecclestone 's `` fantastic '' role as the doctor . some great character from the past return , especially Elisabeth Sladen as Sarah Jane Smith and Jon Leeson as the voice of k9 in `` School Reunion '' . it be also good to see Harriet Jones and the Lady Cassandra return from Series 1 and , of course , the Daleks -- include a scene that go further than the head-crushing scene in `` Dalek '' from Series 1 in make the plunger appendage no longer look quite as silly . as the Daleks do in Series 1 , the Cybermen make a great return , be much scarier than in the original series . the season end with perhaps the most moving goodbye in the history of the series . `` Doctor who Confidential '' and the commentary provide the same fun background information as for the Series 1 dvd , with the -lrb- too short -rrb- gag reel , David Tennant 's extensive video diary , and the new picture in picture format for select commentary be welcome addition . the one most unwelcome addition be the forced viewing of the ad for the Series 1 box set and the BBC America cable network upon first loading -lrb- or reset -rrb- the first disk .