How would you do it? 120 Gallon from scratch

[Mikey B]

Greetings everyone...I've really enjoyed the information and "entertainment" that you post on this site.
I'm just getting started on my first reef tank journey.
I have a 120 G (48x24x24) reef tank, a 50 G (36x18x18) sump, and a stand coming in a couple of weeks.
I've been reading and researching for weeks. If you were in my shoes and wanted to plan far ahead for any possible living addition to the tank, what would your set up look like? why would you do it that way? and where would you buy the components?
Maybe suggest the money-no-option route and the lets-be-reasonable route. Thank you in advance for any suggestions

Mike