What scale to use in a top-down game?

[tfb]

     So I've got my little game of circles running around shooting each other when I realized i need to set a scale of feet to pixels. My calculations are starting to use fps (feet per second) for some things and having 1 foot for 1 pixel just doesn't really work :)
   Now, I know i should have pre-planned something like this but it just slipped my mind.
   I also know that scale depends on a lot of things such as 'height' of the camera, how big the characters are, etc. I'd just like to know what/how others decide on it.
   Also, for whatever it's worth, right now my characters are circles of 16 pixel radii, the screen window is whatever pb's default is. I plan on having around 10 on the screen at a time, the camera will be moveable around a play filed that is bigger then the screen.

eager to hear some ideas!

[Juha Kämäräinen]

I dont really know what you are planning, but just make the calculations for the game work regardless of your pixel size?

Artwise just keep everything under some sort of logic and scale of things will come together.