[Cynor]

Besides Kimi Ga, one of the most mature animes I can think of is certainly Elfen Lied. There is a little bit of the whole "do I kiss her" thing going on iirc, but you really aren't going to find an anime that isn't like that imo. Well, except maybe a hentai... But back onto Elfen Lied, there is certainly a good mix of action, drama, and romance. What makes it really mature though is how graphic it is. Full blood/gore and above the waist nudity runs wild in it. I I'm not 100 sure on the name, but a friend of mine said the only more bloody/gorey series he had seen (at the time) was like Berserk I think.


You may also want to check out Fate/Stay Night. It's slightly more on the childish side, but is really a good watch where everything is nicely balanced and the main char isn't totally idiotic about romance and kissing and such.