the 2 I particularly like that you can buy are doepfer lc9 and tiptop mantis
both are mid priced
both are a decent size
both have decent power - good enough for video - so at audio rates very quiet
if you want a more power hungry modules get the mantis
if you want a lot of lower powered modules get the lc9
the pittsburgh modular structure cases are ok but I know nothing about the quality of their power solutions - they are 'reasonably' priced and people like them - they use different sized screws iirc than the usual m3 - iirc they are 40-4(? a us size) and there are no knurlies, if this makes a difference
choose the case around the modules
"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