We had a great trip to NYC. I took along my Pentax K5, of course. In my kit was 35mm f/2.4, recently purchased. Great for street photography giving 50mm focal length equiv on my camera. It's main problem is suffers from softness when open all the way, which is compounded by higher ISO at night. I should have taken the old trusty FA f/1.4 50mm., but I had to sacrifice for space. I also took the crazy wide angle 10-17mm f/4. Fun lens, chromatic aberration not withstanding. The other lens I took was the Limited 50-135mm portrait lens, approximately a 70-200mm on my camera, but much smaller than my actual 70-200mm, which is a large Tamron and gives a 110 to 300mm approximate focal length range. Ironically I sacrificed my extra lenses because we we trying to "carry on everything", but we ended up checking our luggage so I could have taken more. Over all I was pretty happy with the results, but I wont leave w/o the 50mm f1.4 again. 

I have discovered that its best to bump the ISO to get faster shutter speeds when cruising at night. you can always clean up noise in post processing.