I need some input here.

I'm making a office cubicle freebie, and I can do this one of two ways. I can make it with lots of parts, like shelves and cabinets that can be added in and smartpropped, or I can make it all one solid object with lots of mat zones so you can basically just make any and everypart of it invisible or not. Either way, i wanted to make it so that the user could customize it any way they wish.

What do you think is the best way to go?

First option, no two ways about it. Bundle it as a set of props and a scene with them combined. Also, the .blend file if you're feeling really charitable.