I understand that one could use Amex points and some other credit cards points, for any hotel at all (1 cent per point kind of thing) ... So ultimately the OP's question becomes merely 'what is your favorite hotel', unless the OP is limiting it to hotels that have their own points programs...

In fact, that is what I did with Trisara, which was my first luxury hotel stay. I think I did it again with Al Maha. Once i learned that credit cards points are best used for flights, I put an end to that and started paying cash! But even hotels (that are at least notionally "aspirational" [gawd I hate that word...]) such as the Burj al Arab are possible to do on Amex or other cc points, as aforesaid.