To start off with, there is no such thing as "best equipment", "one's food maybe another's poison" as in One's favorite focal length may not be another's favorite focal length.
But personally, I feel that If you do not want to be limited to just street photography, Consider the kit with 18-200 (as kit lens) which can cover "general" photography so you can also explore other areas of photography too.
But for street photography, I think it hovers from ~24mm to around ~100mm (maybe more/less...depends on preferences). I'm not able to recommend any lens here in this region.
not too sure about canon lenses. but i would say a fast lens (f2.8 and below), focal length of 15mm to 50mm would be the best for street unless you like to shoot from afar.. any longer focal length will do (but the size will be a limiting factor for ur portability)
wide angle for me.. it gives quite a wide depth of field and that minimizes the time to do focusing.. street is more about capturing fleeting moments, so you need to be quick, and get in the middle of the action..
your shooting style determines the focal length that you use. some people go for 200mm, to capture the subject with a tight background and not to startle the subject, change the feel and scene.... while others like less than 24mm. which is up close and personal. sometimes the subject gives the "what the!" look amongst others.
while others use 200mm because they're scared to approach too close.
so depending on what your style is, buy the lens. by buying what others recommend, you're using their style, not yours
Bird and sports shooter will say long and fast lens.
Landscape will tell you wider.
Street people, a mix, some people prefer long perspective, some people like more personal perspective, etc etc etc blah blah blah.
Suggest you decide yourself, hearing why people like Mazda, Honda, Mercedes, BMW isn't going to help you make a decision.