Recommended Walk-around Lens for 5DMII

I just can't grasp the sense over other threads so I started this one. Pardon me if it is repeated.

I have already my prime 135 F/2L for Portraiture and I am very happy with the Bokeh and fast-focus, even in low light condition.

I am now in market for a decent Walk-around for my 5D Mark II. I am considering a 24-70 f/2.8L. I would do mostly a portrait within landscape, some landscape and a mixed of everything in the between.

What are other options I may have?

Thanks again for your suggestion