We have a small niche in one corner of the living room, and that had some shelves when we moved in, but they were not great, and besides, we had to completely renew the walls and so we took them out.
Original shelves (and wall color)
During the renovation process
We wanted some thick shelves, and thought of multiplex, 3 or 4 cm thick, so we went to the shop, and found a nice thick kitchen counter. We had it cut into the proper sizes, to the surprise of the operator there, that asked 3 times if we knew that that was a kitchen top.
I then routed a groove on the sides of the shelves, attached a small guide to the wall and sliped the shelves in. I am too lazy to take pictures while making it, so sorry for the lack of those.
This is the result.
That angled piece of wood is a bottle holder, also my own creation, very very simple. I might make a post about it soon! In the first picture you can see it with 3 bottles!