I'd set up the 180 and add "some" of what you want now. Sand and live rock.
I'd get some fish and maybe a "few" easy inexpensive hardy corals.
This year will allow you to play with the tank and learn how all of your new equipment works.
Also - depending on your level of reef keeping experience - this year would allow you some time to get your water chemistry right.
If you already are an experienced reefer - then no great advantage for this first year set-up.
If not - great time to tinker with everything.
Either way - just have some good old reef'n fun !
Again if it was me - I'd keep it simple for now - then when I had to tear it down and move it - I'd do so ... knowing that once I get it set up again in a year from now - I could go all out and rebuild it.
From there ......... go wild !
Stock the reef as you see fit, with some more expensive specimens, and not risk losing them all in the move.
Just what I'd do ........
There ain't NO WAY I could just sit back and look at all that cool reef tank stuff - sitting in a room somewhere or in storage.
I'd have to set it up too
Good luck - sound fun !!!