Don't Overcommit to the Fashionable Right Angle
Fashion is merely a form of ugliness so absolutely unbearable that we have to alter it every six months - Oscar Wilde
The problem with being at the height of fashion is that there will come a time when you are out of date. It's inevitable: there is no way it won't happen. This is fine if you like to redo things, but it's disheartening if you don't want everything to be disposable.
Granite countertops are a perfect example. When we redid our kitchen, they were so popular that there really weren't a lot of other options. We chose a warm colored granite with a fairly discrete pattern. They are the perfect countertop material. Twenty years of harsh abuse has not diminished them in any way (we have NEVER sealed them and they look perfect). They are perfectly level with intact edges and corners. They have a beautiful luster and the small grained pattern actually hides crumbs too well. Yet granite counters were once hyper-fashionable, so now there must be a period where it is out of date. I know that if we sold our house, the new owners would replace them with an inferior material, but by the time the new counters show some wear (which they will, because they aren't granite), they will be unfashionable and the next owner will replace them. We are never moving.
The problem is that a lot of trends seem more classic than they really are, and right angles are a perfect example of this. 99% of your house probably consists of straight lines and right angles. Some homes have chopped off corners or curved walls, but those features are so atypical that they define the house's style (if any of your friends built a house with a curved wall, you will know it because they will have worked it into every conversation). In the garden, curves are easy so they are a lot more common. Classical garden curves tend to be perfect circles, but they are still there. Property lines, driveways, and building bring rectilinear elements to most gardens, but the current trend is a garden design consisting entirely of lego shapes.
I don't have anything against orthogonal designs and I don't think they should be limited to corporate plazas. However, I don't like to see home owners spend enormous amounts of money on super chic hardscape, because I think that the garden is better if you consider hardscape to be permanent. Aside from the expense, removing it is hugely disruptive to your family and your plants. It's really hard to get rid of hardscape without throwing away everything associated with your garden, and if that seems okay then you really don't want to garden.