Well, that's really two questions: which shows have the highest TV ratings? And: which shows are the most popular with anime otaku? TV ratings are always dominated by kids' shows and some shounen shows, shows that air either in early-evening prime time, or on weekend mornings. I'll get to them in a minute.
But otaku tend to watch (or record) shows that air late at night. For them, the runaway favorite show of the new season is Gakuen Utopia Manabi Straight, which airs at 1:30 am Sunday nights.
I'm basing this statement on the number of posts to 2channel, the most popular anime message board in Japan. It seems to represent a kind of mass-audience otaku opinion. Here is a list of the number of threads on 2channel for most of the new shows. Each thread represents about 1000 posts. When one thread fills up, a new thread is started:
|Yes! Precure 5||11|
|Kyoushirou to Towa no Sora||9|
|Master of Epic||6|
|Venus Versus Virus||5|
|Getsumen To Heiki Miina||5|
|Tokyo Majin Gakuen||3|
As you might expect, the top five shows all have moe appeal. But Manabi Straight has about twice as many posts as the next-most-popular show, Hidamari Sketch.
Shoujo shows normally receive extremely short shrift on 2channel. NANA, after three seasons, still has only 12 threads. So I'm surprised how high Nodame Cantabile is ranked, it being based on a manga serialized in a shoujo magazine. The great cast and the staff of Honey & Clover seem to be giving it credibility. Angelique is closer to the normal ranking of shoujo shows on 2channel. I'm also struck by how highly anticipated the kids' magical-girl show Yes! Pretty Cure 5 was. Shows like this don't seem that popular outside Japan.
Pretty Cure is also the one new show that has shown up in the top ten in TV ratings. It just began airing last week -- on Sunday mornings at 8:30 -- and debuted at #7 in the top ten, with a 7.4% share. That was even higher than its predecessor show, Pretty Cure Splash Star, which had a 6.8 for its final episode. It joins shows such as Sazae-san (21.7% rating), Crayon Shin-chan (10.9), Doraemon (9.8), Detective Conan (9.7), Kekkaishi (7.3) and One Piece (6.8) in last week's top ten.
Among late-night anime, Nodame Cantabile had the highest-rated late-night first episode ever, with a 5.4% share, which went up to 5.5% the following week, but has dropped to 4.4% and 3.5% in succeeding weeks. Unfortunately, I have very partial data for other shows: Hidamari Sketch debuted with a 1.2% share, and Getsumen To Heiki Miina has varied between 1.7 and 2.3 in its first month. After Nodame, the top-rated late-night show seems to be Death Note (fall season, 1 am Tuesday nights), which varied between 2.3 and 3.3 over the month.
TV ratings data for the top ten are from Video Research Ltd., and other ratings data are from a site that collates data posted on 2channel and elsewhere.