[Closed] Going 2x10 - what cassette options?

Just get an 11-36. If you are thinking of going 1 x 10, in the future, with an expander ring get an XT cassette.

11-34 or 11-36 are the obvious choices. I run both with different fronts.

I run the 11-34 with the 38/26 on my main bike and find it very trail friendly. Climbs well and is useful for descending. I found 36/24 a bit undergeared. I have had days when I've been surprised to find an 11-36 out back because I forgot i'd had the wheels on a different bike, though...

As above, if there's any intention of fitting an extender at some point go for an XT cassette.

Also, if moving from triple, be aware that the ring offsets and therefore required shifting differences between a triple (or two rings on a triple) and a true double are different. If you have a mystery front shift that isn't quite clean or tends to drop a bit, look here and fit a double specific mech and compatible shifter (pulls are different to compensate for the offset difference).

Just get an 11-36.

This. No real reason to have anything else IMO.

Thanks very much for your thoughts and experiences