It will depend on how much you want to spend and how hands on or hands off you want to be, and what you want to achieve. When this thread was started, things like the Grainfather (other brands may exist too) didn't really exist, so most people cobbled things together. Also you can now fairly eaasily get all grain recipe kits, that have all the ingrediens pre-measured, where we used to need sacks of grans, and all the different grains and adjuncts. So these should be good and fresh, as I think most suppliers just make them up to order.
We do BIAB (Brew in a bag), using a tea urn (40l Buffalo boiler) as the mash tun and boiler, and using a large piece of muslin as a cloth bag to mash the grain in, then lift it out leaving behing the malt in the water. It may not be quite as efficient as a seperate mash tun, and washing (sparging) all the malt sugar from the grain, but it takes less space and equipment. This for us is a good combination of not thousands of pounds of equipment, and hands on enough that we do the brewing ourselves, not some temperature controlled arduino type device. So we probably don't have as much exact confistancy time after time, but it's good fun, and not controlled by robots.
So there are three basics you'll need. Something to mash the grain, something to boil the wort, and something to ferment this in. You might also want something to help to cool down the boiled wort quickly, but some people do just let it cool down on it's own (but this might mean the beer can get a bit hazy if you cool it down in a fridge later).
Happy to try and answer more here too. We're just getting back into all grain after a long break ourselves, so fantastic coincidence with the timing.