So geometry where it's necessary and bump and displacement maps where it's not?

That's usually the rule of thumb in any modelling situation, but the question is, when is it necessary?  Someone who models for themselves will know if a particular object is going to be seen in a closeup, or camera pass, or not.  Typically, if you're modelling a large, full-scale scene like this for distribution, you'll want the small, insignificant things like wall screws, or cracks in the walls, to be done with high quality textures.  However, if you're modelling smaller objects, something like a chair, I'd make the details with geometry.  Geometry will always look better than textures in close-ups, but what is the likelihood of a closeup of a light switch screw in a large full size room, for example? I'd try to make stuff like doorknobs, floorboards, baseboards, and all that kind of thing with geometry though.  It's up to you.  If you want to see how some of the best environment models in the world are done, just take a look at some of the interior scenes in the Evermotion collections.  Evermotion produces some of the most incredibly detailed and realistic interior models ever.  You'll see how they decide what needs to be modelled, and what can be texture driven details.  Chairs, knick-nacks, books, and even loose papers on a desk, are all modelled.  It just looks better, and reacts better with high quality lighting.

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.