I think in the end, what will happen is that we'll end up choosing molten-salt reactors fueled by thorium-232 dissolved in molten fluoride salts as fuel--the so-called liquid fluoride thorium reactor (LFTR).
The advantages to LFTR's are numerous:
1. Thorium-232 is as common in the soil as elemental Lead--indeed, one of the huge problems with rare-Earth element mining is figuring out how to get rid of the thorium. Suddenly, all that thorium is in high demand for nuclear reactor fuel.
2. LFTR's can even use re-processed uranium-235 fuel rods and plutonium-239/241 from dismantled nuclear weapons dissolved in molten fluoride salts as fuel, making it a very viable way to get rid of a huge current nuclear waste problem.
3. You don't need expensive pressurized reactor vessels.
4. The reactor size can be scaled from 40 megawatts to over 1,000 megawatts power output. That means they could be used for powering installations as small as computer server farms all the way up to powering whole cities, and they can generate power 24 hours a day constantly.
5. Because the fuel is in liquid form in the reactor, there is no such thing as a reactor meltdown if the coolant is cut off for any reason.
6. A SCRAM emergency shutdown of the reactor is dumping the liquid fuel out of the reactor quickly, a lot easier to do than the complex safety systems found in today's uranium-fueled reactors.
7. Using closed-loop Brayton turbines to generate power, you eliminate the enormously expensive need for big cooling towers or locating the reactor near a large source of water.
8. The amount of radioactive waste generated is tiny compared to uranium-fueled reactors, and that waste has a radioactive half-life of under 320 years, which means really cheap nuclear waste disposal using disused salt mines or salt domes (if the nuclear medicine industry doesn't grab it first!).
Note that scientists think that the Moon and even Mars may have large quantities of thorium-232 that could be mined. As such, we may enough thorium-232 to power LFTR's for potentially _tens_ of thousands of years at current power consumption rates.