Angel Beats! if you want something that can switch from comedy to drama at the drop of a hat.
The endings really sad (if hopeful) though.

Some other general purpose suggestions:
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Fate/Zero followed by
Fate/Stay Night: Unlimited Blade Works (the tv show, not the film). Zero has a better story, but UBW is the prettiest anime in existence right now and is worth the watch just for that fact alone. You can
see the money pouring out of every shot.
-
Baccano starts out kinda slow but it's worth the watch just for Isaac and Miria's hijinks, without even considering the rest of the show (which only add to it's appeal).
-
Durarara!! is another really great slow burner by the same team that has 4 seasons or so out right now. It definitely takes at least 6 or so episodes to get into it, but it's still a really neat drama/slice of life with a touch of the fantastical added on top that works great for binge watching.
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Sword Art Online is a show people tend to either love or hate. It's important to recognize at the beginning that the show is actually a romance rather than your standard shonen fare (and works much better if you look at the true protagonist not being the main character). It suffers from a few rushed/filler arcs, but IMO the show itself (ignoring any other books/games/etc.) is really good. It tends to be love it or hate it though, as I mentioned before.
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K (sometimes called "the K project") is a pretty cool show if you can stand the heavy male homoerotic overtones that the show really likes to imply at times.
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Kill la Kill takes the ideas of baring skin and going over the top so far that it loops around and crosses the line twice (or maybe three times). If you can't stand the sight of bare skin then it's definitely not the show for you, but if you can stand it it's one of those shows that appears to have already gone as far as it can go by episode 2-3 and then
keeps going, leading to more and more over the top epicness that just keeps getting more and more awesome.