Hmm okay. But I'm using a crop sensor body (D90), so is 35mm prime or 50mm prime better?
35mm should be good for x1.5 factor body...
point to note here is that... we are only sharing based on our personal experiences. It might be similar to your style of shooting , it might be not to your preference. There is no rule saying that you must use a 50mm to shoot street.
Photography is a very personal matter. It really doesn't matter what other people say, because you can never satisfy everyone in this world. everyone is different.
To start off with, 50mm is a range that is not tele and not wide, it is consider as the NORMAL RANGE ( very close to a human vision without any perspective distortion ). If you are using a crop factor camera , then the focal length should be about 35mm. This type of lens is usually very cheap and the image quality is consider very good for that price tag.
By standing nearer to a subject, you can do portraits.
By reversing the lens, or using an extension tube, you can shoot macro.
By shooting several shots and stitching them together, you can get wide angle.
There is really nothing you cannot do with a 50mm lens.
good luck
Billy