Looking for a VN to play, but finding it hard to pick one...

I don't have the most experience with these sorts of games. In fact, I have exactly enough experience to know what I want without knowing where to look for it, you know? So I was hoping for some advice.

Basically, I'm looking for a heavy R18 game with lots of sex, but more importantly LOTS of routes and choices. I'm not one to shy away from reading, but I do want to play a game, you know? I want to be able to read for a few minutes, then make a choice. Read for a few minutes, make a choice, and so on. Not every choice has to be completely game changing, I just want the game to make an effort to involve me. In fact, the reason I never finished Demonbane was that it simply seemed all reading and no choice. Ideally I'd want a game where the first play through allows me to naturally fall into my own route, but successive play throughs become a challenge to get the best ending with every route.

Oh and a HUGE bonus would be able to full screen the game and have it stay in a good looking aspect ratio/resolution.

Any thing you guys know of that would be really good to pick up? No issues buying here.