don't skimp on power... failing to do it's job when you have a case full of modules is annoying at a minimum... and whilst any damage to either the modules or the power supply can usually be repaired it can take quite a while... and diagnosing what's been damaged can take quite a bit of time...
"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