In the past I played a lot of White Wolf games and the games I ran gravitated towards The Hunters Hunted and especially Project Twilight. They had regular people fighting the supernatural with the opportunity to prevail through stoic single mindedness.
These were people and characters I could relate to, operating in a world I knew with goals I could identify with. This was the idea I started with but I didn't want to just create the same games as I'd played. A few tweaks here and there, a different resolution scheme but essentially the same game wouldn't do it.
It was important to me to incorporate the possibility of the supernatural but use our world as the setting. Historically speaking the last time there was widespread interest in, and acceptance of the supernatural, was during the Victorian era. I did some reading put together a few time-lines and discovered that the setting offers a lot of possibilities even apart from anything supernatural. There's also the possibility that if my game is successful I can write a setting for America, specifically the wild west, at some time in the future.
So that's it. My first full roleplaying game will be somewhat supernatural set in the Victorian age. Old-boys networks, the occult, Jack the ripper, cockney mud-larkls, Dracula and science performed for its own sake on stormy nights.
Now a name...