Alright, so basically, lots of ram with a good CPU and an SSD?
The ssd won't really play a particular role on how many bots you can have active at the same time but the speed they will open up and the booting of the os.Stick to a normal HDD
As the other members already stated,you will need a good CPU and yeah,lots of Ram.Since you got the cash,personally,i would go with:
Cpu-Intel i7-4770
Motherboard-GIGABYTE Motherboard B85-HD3(up to 32gb of ram and one of the cheapest in the category)
Ram-GEIL 32GB (4X8GB) DDR3 PC3-12800 1600MHZ(more than enough Ram!)
PSU-THERMALTAKE Power Supply SMART 730W SPS-730MP upto87%(Since this will be a botting machine,meaning it will run around the clock you need one with high efficiency so the electricty bills are cheaper!)
Graphics Card-GIGABYTE VGA R9 280X(3072MB)-(Depending on the software setup(you set it right it won't load your gpu at all even if it's a cheap one,you can cut down your cost here and not spend a lot on the gpu.)
This setup is a beast actually,Linked that rig depending the availability and prices on my country.