f50fan.
I'm in brooklyn. Not many steep hills, but some inclines. Also, doesn't seem like there is a ton of all out speed riding as there are the stop lights and other traffic issues. I'm in my early 30's, and not in the best shape (although I am changing that with this bike!)

Just to follow up.
So I have a 27 inch wheel
16 tooth rear cog
54 tooth chainring
puts my gear inches at at 91.1 and gear ratio at 3.37:1

That's a little ridiculous for a single speed? The guy who I bought the bike from must have been a monster!