I think it depends on the style and atmosphere you want to create in the room. If the room is a formal, traditional one like your picture, then one large showy pendant would look great. However if it is a modern or contemporary room then two ( or more) smaller pendants would be a nice feature. It would also pay to think about how much light you are expecting from the fitting, especially since it is a cathedral ceiling. Do you need the ceiling lights for good general lighting or just for atmosphere. Do you have any photos of your room so we can see a bit more?

It comes in three sizes, as well as only coming in the white. It'll be elegant over your dining table.

Everyone has some valid points and so I would also recommend moving the clock to the kitchen wall and place the wall unit under the mirror. Centre with the table with the additions of some artwork each side if the clock with wooden frames to match the clock. Find a low piece of glass or pottery or a runner to tie in the grey shades. I presume u have a grey lounge suite. Change the lighting as to what was suggested by People Space ARchitects.

Anyone know where to get these matte black pendant lights from?