Heart no Kuni no Alice
Heart no Kuni no Alice is an excellent otome game; the story, setting and cast are all very well done and enjoyable. The capturable characters all have their own quirky charm, despite their inherent insanity, and the seiyuu do a fantastic job of bringing them to life. Alice herself is a wonderful heroine, much closer to the books' version than other adaptations I've seen. She is very intelligent and stands up for herself, making her interactions with the various wacky denizens of Wonderland much more entertaining than in other otome games.
There are only two real caveats, which may or may not be severe depending on the player: first, this is a purely text-based game with little gameplay besides selecting choices; second, the art, while plentiful and bright, may not be to everyone's taste, as it's far less glamorous and a bit more sloppy than that of other dating sims. I also have a few tiny nitpicks with navigating the CG collection and with the music (it's actually decent, but gets very repetitive during long scenes). Overall, though, many of the by-now-requisite options for visual novels are present, and there's an impressive amount of content, just about all of it quite entertaining.