I would get a Buchla Skylab, Elby Serge, Make Noise Shared Black and Gold System, Doepfer A100 system
and Moog Model 15 modular for that wall of Eurorack sound and have plenty of cash left over for custom add on modules.
For example:
https://buchla.com/product/200e-system-4-skylab/
See what Buchla can do:
See what Serge can do
http://www.makenoisemusic.com/synthesizers/shared-system
ANY modular can do arpegiators that is basic thing anything can do that has a sequencer. You also want a good sampler.
Oh and don't forget to get a keyboard controller while you are at it. I like the Korg MS 20.
The Serge, Buchla, Make Noise, and Moog modular will have all that you need. I think it would be wise to find a modular store to visit and try gear out before spending cash. Join a local music group and make friends with modular gear. That helped me a lot and I am still treading cautiously since I don't have tons to blow on the wrong gear.
Also are you planning to play live at all? You probably also want a lunchbox portable setup as well.
Here is what you can do JUST with the MS-20 and Make Noise Shared System:
It can make some killer drums without a drum module too.