I would say, simple, stylish and not too extreme. Add personality to your kitchen with other aspects like art, colour schemes, accessories. Very dark, bright and fussy details date, also features that are essentially style over substance: little fences on shelves, "pilasters", fake mantelpiece shelves, worktop round the ends of units, curved units, extreme large handles, enormo-drawers. In-frame kitchens unless in period houses.
Cheap kitchens date more quickly as they start looking tired, but then maybe that doesn't matter so much.
SpongeBobGrannyPants we have a Howdens Greenwich kitchen in Cashmere (was here when we bought the house). It's a lovely colour and style but the DIY kitchens Carrera Cashmere knocks spots off it for quality. Greenwich is a 15mm melamine faced door with a plastic edge strip and you can see the join. Carrera is a thicker door with a smooth seamless paint finish. I ordered a sample because I want to add a couple of matching units.
The colour looks good with a black worktop though, adds a bit of contrast. With oak worktops I'd go grey, white or off white.
It's funny I think brilliant white Shaker style looks a bit "wrong" too, Gloss Shaker even worse!