I have to admit that Doctor Who is not nowadays, for me, absolute must-see TV. That's no reflection on the show itself, just that it is after all the apotheosis of broad-appeal British light entertainment whereas the few television dramas I go for tend to be US cable output. But I do often find something to enjoy in Who when I see it (when they're not mucking up the Daleks, anyway). And I have great admiration for Russell T Davies, a writer who knows exactly what he's doing and has the chops to pull it off.
In particular, he's succeeded in bringing a depth of feeling to the drama - an emotional dimension that used to be treated quite sketchily, if at all, in the old days. Few TV writers are better at adroitly interplaying "the determination of incident" and "the illumination of character" as Henry James put it.
The main lesson I try to learn from RTD is to tell my stories with pizzazz and showmanship. If old Who was watched from behind the sofa, new Who is definitely on the edge of the seat. Here's an edited interview Davies gave at BAFTA where he talks about his impressive regeneration of the series.
That said, I suspect the show will be more to my taste next season with Stephen Moffat in charge. Allez, Monsieur Davies!