Examples of the desired types of images could help in selecting the right camera and lens..."street" might mean that camera-in-the-face style of Eric Kim, or it might mean from farther away, Gary Winogrand style,etc..
Hard to say what the best is...some people like that wide-angle, close-in look, which I personally seldom like, and yet on some pictures , being very close to the scene is a great way to show things. Some photos are shot from farther back, and seem more voyeuristic, more "dispassionate observer" style, which is what I prefer. Some "street" involves showing people reacting to the camera (Kim's work, for example, often features this) from close-up; other people like to show people unaware of the camera, or from longer distances, with longer lenses. I like the latter style. I like seeing "telephoto glimpses" of street and city life. For that, the longer lenses work best.
Lotta cameras out there to choose from! I would NOT rule out a good cellphone camera for some situations. Seriously. Fuji X-series, small compacts from Olympus or Sony, the Canon PowerShot G-series models, all pretty nice machines; a good deal of war zone work has been done with these "amateur" cameras by a select few modern journalists who want to look NOT like photographers or war correspondent photographers, so I would not under-estimate the power of a cellphone camera or a point and shoot type or at least a P&S-sized camera to help you blend in more than if you had a big, black, d-slr.
I think mirrorless or "consumer-type" cameras help many people feel less-threatened than big, black, pro-sized cameras.