I would replace my dyson chordless like for like, perhaps putting a second upstairs. I would also just replace my range master cooker - 5 ring gas hob, electric grill, 2 electric ovens - I absolutely love it.
Miele appliances in kitchen and utility (this is imagining my dream home - there is a separate utility!). American fridge freezer but also a separate chest freezer in utility or shed.
I would also get a kenwood chef again, or else the one on bake off with the glass bowls. But with more attachments (I have a blender and food processor attachments but there are some others I'd like in the catalogue). And a better storage system for appliances (including a drawer/segment for smaller bits and blades to be stored safely near the appliance itself). I think though that I would get a smaller slow cooker - it's great but I don't use it much as I got too big a size for our family so it needs more stuff in it and a lot more liquid.
I would love a proper power shower and either large walk in flat floor shower or fully open shower room with underfloor heating and heated towel rail (for just after showers) and decent fan system (to remove heat and condensation once my spa session is over). Also, double sink, plenty of counter space/decent cupboards for bottles and potions, and an anti-fog mirror and good lighting.
I agree that lots of IKEA is very good, some of the high end things but also some of the very cheap pieces too. DHs favourite chair is not available anymore so we'd probably get an Eames chair to replace that, but I have the standard bent wood chair with a leather cushion rather than the fabric cushion and I would get that again. And I love having a few folding kitchen chairs tucked away for spare bedroom use, extending our dining group in the kitchen or taking outdoors if we have more people than outside chairs.
Wood burning stove definitely would return.
I would probably buy a different bed as the mattress is starting to fail (over 20 years old now), but dd would want her IKEA bed replaced as it is (she's trialled a few mattresses to get her perfect set up).
Some of my things are irreplaceable- like my DGM's roasting tins and trays for baking tartlets. But I think it would be nice to put together a house in a coherent style and our current tastes (which have evolved over the years). And to get a matching set of tools for the kitchen, and well though out storage solutions everywhere rather than the mish mash that we currently put up with.