I'd suggest the 70-200F4 IS and the 17-40 f4. (yea, the newer 16-35F4 has better IQ but the 17-40 is readily available second hand at good prices).
You already have the 50 f1.8ii.
The above is good 3 lens setup.
Stole the words out of my mouth Shocolite.
17-40 L for the Wide Angle and the 70-200 f/4 L IS. Image Stabilization in that range really comes in handy. It also stabilizes in the View Finder to achieve critical focus faster and more reliable.