im not sure why some people think that you cant ride up a hill on a SS bike...its really not bad, Ive done multiple long and hilly rides in groups of roadies on a fixed gear. for riding manhattan, 44:16 will get you everywhere you need to go, if you feel like you might need more power, drop it down a bit.
SS bikes are just so much nicer to ride. I sold my fixed gear to get a road bike, thinking i would enjoy longer rides more....well now that i have a road bike, i want the fixed gear back. theres a reason, beyond trend, that so many people in nyc ride SS/fixed.