Define "best".
Best for the money?
Absolute best optics?
Best for what purpose? There are some specialty lenses that only certain manufactureres make.
Best selection?
Like binoculars or riflescopes, you get what you pay for.
Canon has the best selection, and makes some very superior pro-quality lenses. Check out those white lenses on the sidelines of football games...all Canon. Canon also makes some specialty lenses that are unavailable elsewhere. I'm a Canon user, and I like what Canon has done in the photography area.
That being said, of course many companies make comparable quality lenses.
