I disagree about buffered 4 channel mults being the way to go:
1 you only need buffered mults for v/oct
2 passives are significantly cheaper and you can spread them out better around the rack - and if you don't have space for them you can use headphone splitters etc just as well (or an actual passive mult)
vcas are an essential part of modular synthesis - @sacguy71 - you are just starting to learn why you can never have enough vcas!!!!
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities