My parents' old house had a wonderful oak front staircase that my six siblings and I used to race up and down, taking them two or three at a time, with only a casual hold on the railing. I don't know how we managed to never slip or fall. Now, the timber backstairs were steep, and had narrow treads and were poorly lit. We NEVER ran up or down them, but held tightly to the railing and hoped to heck we managed to stay upright. As an adult, my previous home had carpeted stairs, which I slipped on (wearing socks) and fell down twice, though thankfully I was closer to the bottom than the top. My current home has timber stairs with three narrow stainless steel runners stood on edge and inset horizontally across the front of each tread (this is supposed to help reduce risk of slips). I doubt I will get over the anxiety of taking another tumble, so I never go down them wearing socks, and if barefoot, I hold onto the railing for dear life and take it nice and slow. So far so good.

If there is a storage cupboard underneath the stairs, then I think its best to let go of the open risers. At the end of the day when it comes to stairs, I think you need to make simple decisions, don't complicate it. Sometimes spaces fuss over stairs and they can look great, but they are very impractical, expensive and dangerous. I think if you live in a house with no kids and no elderly, then you can lash out and go for something with more design risk. I think the timber stair profile shown in your picture looks great, and would work well with your vertical timber beam balustrade. However timber stairs can be noisy and quite slippery. If you are using carpet upstairs then you could consider running carpet all the way down the stairs. Don't do the half half thing. In order to finish the edge of the stairs neatly, I would edge the stairs with the plaster finish continuing from the cupboard wall, all the way up to the edge of the stairs and making an edge profile for the carpet to be neatly tucked into. By doing this you could still get the stepping silhouette which would look very cool. Then the beams could run off the plaster surface and not the edge of the carpet. Ultimately carpet may be annoying to have to vacuum, but it is a lot quieter, considerably cheaper and safer than timber stairs. Hope that helps. Good luck with it.

I think that ceaserstone or marble would compete too much with your tiles and could look odd because of that. In the examples you provide, the one lot of marble stairs are with a very plain tile and the other looks like it matches the floor exactly. Your tiles have a bit of a swirly pattern so unless you chose a very plain stone/marble it would clash IMO. Also, ceasarstone can chip and I don't think it would be a very practical option for stairs. Timber would add a bit of warmth to your whole sleek look while still looking modern, and be something to tie your front door in with so it isn't the only warm looking thing in your whole light coloured area.

I really like the pic that LesleyH posted. The wooden rail will be 'warmer' to the touch too, show less dirt and tie is with the stairs beautifully.....I thin it will 'ground' the whole look because, if I remember rightly, the stairs and front door are the only wooden features and the rest is a lot of very modern light grey/white/shiny features. I think another touch of warmth in the wood will be beautiful.