With street photography it is all about carrying light and snapping a nice shot every time.
Prime lenses are ideal for street photography because they are small and compact.
Prime lenses have a set focal length, so that means no zooming. In street photography your legs are the zoom. Having a set focal length helps you think about what kind of shot you are going to get as soon as you want to take it. These lenses let you get up close and personal with your subject without looking very obvious. The most common type of prime lenses that street photographers use are 35mm or 50mm lenses.
Prime lenses are also great for portrait photography. They will give you a greater shallow depth of field due to the wider maximum aperture than a zoom lens at the same focal length.
Wide angle lenses are great for when you want to capture the environment around the subject. The most popular wide angle lenses for both Canon and Nikons is a Sigma 35mm f/1.4 (cheaper option is a Canon 35mm f/2 but keep it mind it's a tad bit slower in speed).
Telephoto lenses are what many professional portrait photographers use. These lenses allows you to get up close to your subject without any "fuzziness". These are also good lenses to use when you want to make your subject stand out from the background, which gives your photo a real 3-D effect. Some popular telephoto lenses are: Canon EF 70-200mm f/2.8L, Tamron SP 70-200mm f/2.8 or even the Canon EF 70-200mm f/4L which is a great quality lens if your'e on a budget.
For landscape photography you want to ensure you capture the whole scene of the landscape. For this type of photography the best type of lens to use is a wide angle lens with a focal length between 21mm and 35mm. This type of lens allows you to take a close up without a lot of distortion.
So what's your favorite lens?