What I'd find interesting in an RPG plot? Or any plot, for that matter?

If the villain was the protagonist's SPOUSE. Imagine if your wife/husband was the one who started tearing apart the world, and you were the only one who was in the position to stop them.

Protagonist's parent being a villain = DONE (Star Wars, Darth Vader). Protagonist's sibling being a villain = DONE (Final Fantasy II, Golbez). But tell me a time when the person ripping apart the world was the same person that the protagonist was in love with?

Anyone ever witnessed an instance of this in any medium of fiction, ever?

Hmmm, interesting question!

The only thing I can think of off the top of my head, and this would be a spoiler I suppose, is Silent Hill 2.

That's the only game I know of where the final boss is your wife, although the circumstances are not that simple, obviously.

I have the feeling there's more though, there's gotta be.

Before anyone else mentions it,

Final Fantasy VIII

: [hidden]Cid's wife, Edea; although, she's not the ultimate big bad, she snaps out of it well before the end of the game, and Cid isn't the main protagonist, either. Also, the relationship between Cid and Edea wasn't all that well developed, either.[end hide]

Nuku-Nuku kinda fits, though it's the ex-wife in this case, and not quite the /main/ character.

I'd say there's a lack of protagonists with husbands/wives period. I guess it's a natural result of so many games starring characters in their teens or early twenties. And since console gamers seem to be dominated by guys at those ages, most of them would probably be more interested in ogling some loose sexpot or watching the exciting beginning of a relationship develop than see a "boring" established marriage that they can't relate to.

That said, even though it doesn't fit the topic, I've always found Lufia II pretty novel with how [spoiler]: the hero breaks up with the love interest he started the game with since it's clear that they don't fit each other, falls in love with another party member, gets married, and has a kid, all smack in the middle of the game, with them even living peacefully for a year until they realize that the world still isn't safe and get dragged back into the fight.

Another thing that I haven't seen from the CRPG days (like Wizardry IV) is where you actually pay the villain trying to take over the world (or kill the hero).