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Unlike rims, high quality hubs can last wins if serviced regularly and used with correct cassette.
I serviced Shimano hubs regularly at work, they're wonderfully easy to fine tune with no drag (providing it didn't get pitted).
Only issues is the titanium freehubs body can be prone to sprocket cutting away (not a problem per se), unless you use expensive cassette with alu carrier.
Personally, Ultegra is my choice due to steel freehubs body.
You don't need posh rims. Kinlins are fine.
DA hubs are very nice and with them comes the option of using your favourite builder. 28 / 32 spokes will be easier to keep true and functionaly even tension than lower counts.
I'd probably save cx-rays for 'fast' wheels.