46:16 is pretty much the mid-point ratio for fixed-gear riding on the road.
So get a higher gear if you ride in a hilly area, and lower if in a flatter area.
But don't take my word for it, head over to your LBS and try out some gear ratios first, and find out which you prefer. I suggest getting one that's slightly uncomfortable, since your body needs to adjust to fixed anyway, and you can actually train and improve because of it.