For the moment, there are actually several options for what concern high-energy colliders:

• a linear electron-positron collider operating at high-energy. One of the main goal is to study the Higgs and the top quark in detail, and unraveling new phenomena if they are close by in energy. See here for instance.
• a circular electron-positron collider operating at high-energies ranging from the Z-boson mass to the top-antitop threshold. This will allow to measure at an unprecedented accuracy the Standard Model (and probe new phenomena indirectly). See here for instance.
• a circular proton proton collider at 100 TeV aiming to discover new physics (and also accurately measure the SM). This one was the topic of this post. (Links are given above).

Which option is better is very hard to tell today. A decision should be made in 2018. For the moment, it is time to evaluate the physics prospects of all of them, the timeline, the costs, etc... and we also wait for inputs from the LHC of course.