The above places are all good.Each city is in it sort, distinctively different. Kyoto does feel alot more traditional, Osaka is it's own thing entirely,I feel like Osaka is alot more energetic and is sort of like a rival feel to Tokyo,even though they're meant to be similar,there culture is distinctively different, so don't think that visiting Tokyo means you shouldn't visit Osaka even if others say so.Tokyo is Tokyo,feels really busy and large, just like a major capital should.(alot more busy then Sydney though,(not saying Sydney is capital lol)).
If you're going after HSC that means around the winter time,so if you want to do some snow activities I really suggest going to Sapporo and going skiing there,it's a major destination during winter and they have some good winter facilities plus awesome winter festivals(ice sculptures and other cool things).
Apart from what others have said, Nara is a pretty good place to visit for the history but also the wild deer which roam around the temple and which you can feed and touch. Takayama is also a cool place, it's got a preserved from history town, which you can walk around and get lots of souvenirs and stuff(there's stuff like ninjas and all that haha, lots of movies film there!). Himeji near Hiroshima is a cool place to see the huge feudal castle,among other things.
Really though if you're mostly into just pop culture stuff,Osaka and Tokyo will be enough.In Tokyo alone you can spend around 2 weeks there with still some stuff to see after, and you definitely wont be bored. Osaka you can spend around a week,so that's basically your holiday planned for the pop culture scene. If you got a few days to spare definitely head up to Kyoto or Nara,each city really has it's own feel apart from fundamentals.
