hi all. i'm new here and not exactly familiar with the cycling nomenclature so please bear with me. i'm looking for a bike to use on the city streets(nyc), light trails, and also for fitness. so i guess i'm looking for something that can take the beating of the streets, is good to train on, and also comfortable enough to ride leisurely(not too hunched over all the time). a light bike is also a plus since i'll be carrying it up and down stairs quite a bit. i'd like to spend only about $500-$700.
googling i came across the following three bikes that seem to fit my needs:
