I quite recently bought a smc-m 40mm 2.8 "pancake", mostly for its compactness (great pocketable combination with a me/me super/super A body). But I found myself using it most of the time, as it seems to hit some sweetspot in tems of angle of view, at least for me. I found the 50mm a bit too narrow-fielded for street photography (at least for the streets of the city I live in). I also use a 28mm, which is quite compact (smc-m f/2.8). I take it with me most of the time, as it fits well in a jacket pocket. The 28mm is my default option when the environment isn't that crowded or when I can get close to the subject. But most often the interesting, fleeting things I spot on the street are some meters away, where a 28mm lens would introduce too many undesired side elements in the composition. Anyway, this is the pair of lenses I take with me 90% of the time when shooting 35mm street. Occasionally I use a 17mm (tokina), as it goes past that focal length where people still realize they are in the picture, so they don't modify their attitude. But for really wide shots I use a 14mm samyang. Its problem is that it is comparativelly large and cumbersome, so I leave it at home almost every time.