Right, no need to use super expensive stones if they will be hidden by plants. The same with driftwood. Although at least for me, one of the most exciting parts of a new layout is going to the countryside to look for materials, something that usually implies planing two or three trips with the family. This is another cross-cutting benefit of the hobby!
I guess the point is to be able to produce something that looks nice for you (the tank will be in your home and you will want to enjoy it) but also in the pictures you take... And this combination is really difficult to achieve. In my past layouts, tanks were very pleasant to the eye but very flat when photographed. And I really don't want to produce something nice for pictures but weird to the eye as it happens in a lot of IAPLC entries with very strange layouts, solely produced for being shot and presented to a contest.
Another thing I have learnt is to keep things as simple as possible. My first layouts were crowded of plants. You want to try a lot of them and I think it is really nice to learn growing habits, but in most cases selecting the 3-4 species you can master and that fit well in your layout idea (as previous posters mention, plants that once grown will be aligned with your layout in terms of size, shape and colour), gives you a more pleasant aquascape and your hardscape can really contribute to the final result as the hardscape and plants will have more chances of being balanced.
Sounds easy but I'm struggling right now with all this!
Jordi