Gary...I adore my Quooker tap. I was completely against the idea too as they are stupid sums of money and all the tanks and filters take up a chunk of space...but was persuaded by folk on here...they were right. Instant boiling water is so useful, especially if located close to where you cook. Ours is the prep sink tap. Getting the 'flex' version, which can be pulled out, has worked very well.
Two dishwashers is the best thing I have ever owned in my life. All the advantages of F&P dish drawers and none of the disadvantages. My wife agrees....and that is worth the weight of the dishwashers in gold. Ours are Miele and are pretty far up the range, get amazing reviews from places like Which, and suffer none of the problems that Mark Palmer seems to have had with his.
I'm in love with my Gaggenau ovens (one plumbed-in combi-steam and two 76cm ones for cooking pigs) and the Bora Pro induction hob, which extracts with amazing vigour when searing steaks or frying oily fish - and has proper knobs. Glad to have moved on from the idea that gas is the ne plus ultra; induction is so much better overall.
The thing we did that delivered the most value was thinking very carefully about layout and flow. We have a fairly linear flow that starts with the larder and fridge/freezer, goes via an adjacent large prep area (with a prep sink nearby), then onto the ovens and hob and ends with the dishwashers, another sink and space for clearing/cleaning. Perhaps sounds obvious but I don't think we would have done it that way had I not read an article by a professional chef and discussed things with Mark P who'd done a great job designing his old kitchen. And it tends not to be how many kitchen designers think.
So far (as the kitchen isn't quite finished as the stone company went into lock down just as they were due to template - and haven't re-emerged) the only thing I'd do differently is to think more carefully about the exact size, shape and purpose of every cupboard and drawer. We did this for many of them, and wanted to do it for everything, but lost the will to live as it's a painful process. Hence we ended up just having a load of generic drawers and then figuring out how best to use them. It is then a bit annoying when a desired combination of items is 2mm too big in a given direction.
Good luck. Lots of good tips on the other kitchen thread too.