>>4171811>>4171810>>4171795each of these depend on how close you're going to be to your subject (or how close you want to be), and that will probably depend on what type of place it is.
a marketplace in hong kong is going to be awesome with 28mm because that's how close you are to everyone. it pulls the background in a little bit and the slight distortion makes the scene look more intense. great. i can smell everyone i photograph and its impossible to not be noticed.
50mm is a lot of fun in most situations, but you stand 2m away instead of <1m. im more likely to see something happening at this distance and get the shot than i am with 28 or 35 where i need to creep up and get closer first.
35mm is fantastic and i usually have it pre-focused to 1.5m. if you know where to stand and you know how to compose an image its perfectly fine. its good, even.