The best game I have played so far is Discipline, which is perfect for my taste except for the endings. (I don’t really like any of the endings.) I think, that Bible Black might come close, when I get that game. But we will soon see about that.
To a lesser degree I also like The Sagara Family and Princess Waltz. But my next games can easily beat them, because they both have some very weak points. The two games are acceptable and worth the money but not really that good.
I have also played the following games. But I don’t like any of them:
XChange (you probably have to be a bisexual tranvestite yourself to like that game)
Gibo Stepmother’s Sin (I just don’t like any of the characters in the game (including the protagonist))
Crescendo (a lot of boring talk without action and a lot of too naive, too romantic and unrealistic story-lines. If you don’t use a guide then you will probably also miss all the H-scenes. The game is much too boring to play over and over just to search for other endings and the H-scenes.)