We've had our kitchen for 15 years now, and I'm still happy with it. Big thumbs-up for the deep pan drawers, built-in recycling bin, contrasting high-level cupboards with glass inserts, and lots of useful alcoves for chopping boards and towel rails. There are a few things I'd change:
Firstly, there is plenty of worktop, but it's not quite where I need it to be. Chopping veg and preparing food to cook you tend to do near the hob, so I'm corralled into quite a small area. Meanwhile there are acres of under-used worktop at the other side of the kitchen - great for appliances, but not for prep. I wish I'd thought more about that.
Secondly, there's a pinch-point in the middle of the room, so of course, that's where we chose to put the dishwasher. Duh. When the dishwasher is open you can't get past, which is annoying. Should have moved it to the other side of the sink.
I wouldn't bother with one of those big chrome extractor hoods if I were planning a kitchen now. There are much nicer/more modern extractors.
Lastly, we bought a cheap built-in microwave from B&Q, which gave up the ghost after 18 months. It turned out to be a weird non-standard height, and we have never found one to fit the space. I the end, we had to turn that section into a shelf, and slot in a free-standing one. Not the worst thing in the world, but it annoyed me for ages. If you're going for built-in, go for quality. The Neff oven, for example, is nearly 20 years old and still going strong (was already in the house when we bought it).