This is a very good question! It is actually impossible to predict what the next Pangaea or supercontinent will look like, but we can make some guesses. Today there are several large continents that are separated by ocean basins. Ocean crust grows at mid-ocean ridges and is recycled back into the mantle at subduction zones. When ocean crust is recycled back into the mantle faster than it grows at ridges, ocean basins “close”, and continents come together to form supercontinents. Today, the Pacific Ocean crust is being recycled back into the mantle faster than it is being created at a mid-ocean ridge (known as the “East Pacific Rise”), so this ocean is actually closing (Hamilton, 2007). The Atlantic Ocean crust is being created at the “Mid-Atlantic Ridge”, but it is not being recycled at any subduction zones, so this ocean basin is growing.

I made cartoon cross sections of these two oceans to show what they might look like if you cut across them and could look at the inside.

You can see that they have very different features. The Pacific is surrounded by subduction zones, while the Atlantic doesn’t have any subduction occurring at its edges. This means that the east coasts of North and South America and the west coasts of Europe and Africa won’t join in a supercontinent any time soon. They are actually growing farther apart as the Atlantic Ocean opens up between them. On the other hand, the east coast of Asia and the west coasts of North and South America may come together many millions of years from now. If that happens, the islands in the Pacific, like the Marianas islands, the Philippines, and Japan will be sandwiched in between. It would take a VERY long time for the Pacific Ocean to fully close though (many millions of years). Plate tectonics (how the ocean and continent plates move on the surface of the earth) is very complicated, so it is impossible to predict if that will really happen. There have been many supercontinents in the history of the earth (Rodinia, Gondwana, Pangaea). It is certain that new supercontinents will form in tens or hundreds of millions of years from now, but it is hard to predict what they will look like.

References
Hamilton, W. B. (2007). Driving mechanism and 3-D circulation of plate tectonics. Geological Society of America Special Papers, 433, 1-25.

Good question. This is the subject of speculation because it depends on where rifts form and where the continents move in the next few hundred million years. Most of the continents, all except South America and Antarctica, are moving north and colliding as they do so, thereby creating a new northern continent in the process. This new northern continent will have no Mediterranean (because Africa will have closed it), and Australia will have rammed into Southeast Asia, and North America will have joined with Eurasia both in the east (across the north Atlantic) and in the west (Alaska-Siberia), turning the Arctic Ocean into an inland sea. However, South America will continue drifting west, making it an island continent again as it pulls free of North America, and Antarctica will stay where it is for the foreseeable future.

However, unpredictable things happen. Eastern Africa is currently rifting away into three chunks: Arabia, which is colliding with Asia much as India has, Sudan, which includes the entire eastern side of Africa, and Tanzania, which is the round-ish block including Lake Victoria, in the center. They're all moving east (except Arabia, which is moving north). However, there is an example of a failed rift in North America that would have torn North America apart roughly through the location of the present-day state of Missouri, but rifting stopped for some reason.

Will the African rift continue? And what new rifts will form that might, for example, move Antarctica off of the South Pole so that it can interact with the other continents again? These things we don't know how to predict - yet.