Welcome to the forum Gyono,
In reality, the lens you choose is what you intend to shoot, this is a personal choice.. The 18-200 captures most shots I want in street photography, festivals, marathons and the like without having to change a lens and miss a shot. For surfing shots I use a 70-300mm and at times find it falls short in length. For wild life and birds the wild life shooters on the forum recommend a minimum of 400mm.
Like many here suggesting lenses, the above is a personal choice for what I shoot and would be of no use to others, the answer for what lens you want is simple, "what do you intend to shoot and in what lighting conditions."