Wheels are the place you will notice weight the most.
Get some decent wheels (particularly the rims) and then buy lower spec things like cassete etc to offset the cost.
Current deore is very good but I would probably go SLX for the chainrings over Deore unless Deore now has the nicer ones. Maybe get SLX/XT on things that are less likely to wear out/break – cranks, shifters.
Good deals around on the current SLX brakes too.
tbh I would be happy forgoing expensive hubs like Hope ones for something cheaper and using the money on the rim as this is where weight and strength matters most. It all depends if you want cartridge bearings and the ability to switch to a different type of axle (eg 15mm, 20mm) at a later date. Others may say otherwise but it all depends on what you can afford.