I like the Contigo brand stainless bottles.
They have standard size bottles up to 20 oz or 24 oz.
A couple of different types of spouts, but most of the new ones have an auto push-button open.
Good shape that fits in most bottle cages quite well.
I've tried a couple of different spouts, and am not sure which one is "the best".
A little rattling in certain metal cages. Choose a bottle with raw stainless and not a fancy color.
Most of them will work with hot or cold drinks, and the heat retention is 2x or 3x better than the plastic bottles that I've used.