I had a fab kitchen and then moved. No kitchen for over ten years. Got round to it, and best things have been mentioned:
Quooker Cube - used all the time.
Drawers instead of cupboards under worktops and a tall larder with pull out drawers.
Plenty of sockets.
Bins in a drawer - rubbish, recycling and peelings etc for compost out of sight.
Pull out tap to rinse sink, wash rice, veg etc
Not worth it ... considered expensive worktops, but settled on laminate, so we could afford the Quooker. Happy with that.
We bought a range cooker before having the kitchen done. There are times I use both ovens. Don't think I've ever used all gas rings. I think I would rather have more drawers and a built in oven, maybe two and a four burner hob.
Dishwasher - have downsized from household of seven to four, and I think we may not need a dishwasher any more. Really useful when doing a lot of cooking, but 75% of the time, I could easily just wash up in the sink. Dishwasher not heating water today, so I may be testing that thesis over next week or two.