If you are not going to be overclocking the RAM or the GPU, you don't need to watercool anything other than the CPU. And you don't even really need to liquid cool that but it certainly won't hurt. Of course, later if you decide to you will have the freedom to do so since you'll already have the setup. Are you planning to use an AIO or a custom loop? I'm assuming a custom loop since you mentioned RAM and GPU.
You really don't need all that. That GPU is already superclocked and has a good cooling solution included. I'd focus more on the case airflow.
If you keep a good supply of ambient air coming into the case and have sufficient exhaust out to get rid of the heat coming off that card, an AIO cpu cooler would take care of the processor and your case fan solution should take care of the rest of the board components especially if you have no plans to further overclock the GPU, to overclock the RAM or to overclock the CPU.