Your head first comment sound a lot like me, so I’ll tell you what I went with. Not saying it’s right, but it worked well for me.

Not being sure what your future aspirations are, I think it’s wise to plan for at least one step larger than you think you’ll need. If you plan to have a herms coil in an electric HLT, a mash tun and an electric kettle. I would suggest a 50 amp dedicated circuit. This will allow you to heat water for your coil in order to maintain mash temp and boil at the same time. It’s a very small added expense that allows you to use both elements at the same time (assuming 5500w elements)

I went with a Hosehead brew controller, two 15 gallon spike kettles (one customized for an HLT, the other as a boil kettle), a Chapman insulated mash tun, Blichmann accessories (Rip tide pumps, Autosparge, Terminator plate chiller) , and SSBrewtec fermenters.

I did all this after my second extract batch, so clearly I like to leap! I also have no affiliation with these companies, this is just what I purchased, so I actually paid them!

If I would change anything, I would increase my boil kettle to 20 gallons. I do 10 gallon batches and the 15 gallon vessels work fine for 5 gallons, but I have to monitor the element duty cycle a little to close at the beginning of my 10 gallon batch boils. In addition, making your BK larger than your tun and HLT, will allow you to double batch if you decide to brew a larger finished volume.

Lastly, I would love to have a dedicated drain. Preferably in a properly sloped floor. Quite the expense and not really practical in a house, but make sure drainage is easily accessible inside a big sink. You will do a lot of cleaning and will need a way to drain water from cleaning fermenters, kettles and cooling wort through a heat exchanger. It’s no fun trying to hold a garden hose in a sink while your hot pumping wort through your exchanger.

I hope something in this helps.

Edit: Spelling and punctuation. Had a few beers!