Since most of the modern MD packages support calculations on GPUs, i would recommend you to get a workstation with multiple CUDA GPUs. Several Tesla k40 will be a good choice. RAM is always not enough, so it's better to get as much as you can (at least 32GB, but i would recommend >64GB). Also, i recommend you to get a DDR4 type RAM. CPU should have as many cores as you have GPUs installed in your system, since most of calculations in such systems are done by GPU, the power of CPU is not critical.
Since most of the modern MD packages support calculations on GPUs, i would recommend you to get a workstation with multiple CUDA GPUs. Several Tesla k40 will be a good choice. RAM is always not enough, so it's better to get as much as you can (at least 32GB, but i would recommend >64GB). Also, i recommend you to get a DDR4 type RAM. CPU should have as many cores as you have GPUs installed in your system, since most of calculations in such systems are done by GPU, the power of CPU is not critical.