Go to any video game store, especially if you're anywhere near Akihabara in Tokyo.
I'd venture to say it's about half and half for Japan-only titles, maybe more, depending on how raunchy the shop is.
Having not read much of the thread, I'll hazard a few suggestions
Shingetsutan Tsukihime: A few years old, 12 eps. Based on a graphic-novel type game. There was a whole lot that I liked, and not a lot I didn't. I didn't know that I would get as emotionally attached to the characters as I did.
Ergo Proxy - post-apocalyptic cyberpunk awesome
My-HiME - yay boobs
Also fuck all you haters Avatar is awesome.
I really get the feeling that he hasn't been on for a while, and that the administration dealt with our bitching.
I wager he's in for a surprise when he remembers his password.
Aside from featuring full-blown unavoidable nudity, you could have a (admittedly offscreen) threesome at the start of the fucking game.
Talk about accessible.
I started out as LokiSeraph, which I made on a whim when starting a game once, but gravitated to Fenrir after a while.
Mostly because a giant wolf that eats Odin, and whose spawn consumes the sun and moon, is badass.