Hibike! Euphonium: (content is totally biased) as an ex concert band musician, I find the intro to be quite realistic, but from what I've seen yet, this could be going into something great if they don't messed it up!
Denpa Kyoushi: I don't know what to think really, it's really unstable, some part were awesome in my opinion but some of it were really boring and stale, but if they take a great direction, I think this could be good.
Ore Monogatari: Yo, everyone wants a friend like Takeo, holy crap, he's so freaking nice and everything, I love romance anime, so probably being one of the few non-harem romance anime airing this season(with Nagato but I'm currently disappoint with that one), this one win my bet automatically, probably one of my favorite this season.
Kyoukai no Rinne: I'm finding this one quite boring at the moment, I had problem not falling asleep on it, need to see more to make a more concrete decision.
Nisekoi: Does what it has to do, but so little content in that episode, quite disappointing for an opener, considering it was one of the most awaited fan service this season I think.