I recommend Wizardry 8

 Wizardry 8 is an RPG that has a lot of grinding but is relaxing and peaceful, with slow turn-based combat, based on an HP / AC spell system that will be familiar to any RPG player.

I recommend it because:

1. The voice actors are very good. Make sure to choose the voices of your characters carefully. The NPCs are excellent.
2. It is sufficiently complex that I keep learning new things about it every time I play it.
3. The story is about saving the world, but is not gloomy (like Diablo) or cruel (like Warhammer and Warhammer 40K -- both of which I like)

If you choose to play Wizardry 8, you will need guides, especially if you choose what I think is an optimal outcome (which I cannot reveal without spoilers -- just google "alliance wizardry 8" although there is more than one alliance in the game.

In a game such as this one, the combat has to be interesting because it's most of what you are doing. It consistently gives you interesting choices, and also makes you think about how the effectiveness of alternative groups of character skills in different party arrangements.

The graphics are _old_ but generally are very good. Some locations will require you to look up a map. Don't play this game in a rush to the end. Play it to experience the variety of enemies and enemy abilities, to find the various secrets, and to explore every map in order to learn as much as you can about the story.

Do not, however, play this game if you are religious. Even though the end of the game recognizes Judeo-Christian gods, you will be offended by the middle-to-late game.