Do you prefer your water bottle to be made of metal, plastic, glass, or something else? Straw or no straw? How big would you want it? Should the bottle taper down in the bottom, or do you think the sided should stay vertical? Are any of you one of the few people who would like that weird rectangular bottle? Or maybe one of those squishy fold up ones for travel? No handle, flip up handle, mug style handle, or little loop?
Note that I am not affiliated with any water bottle company
Metal. Though there is a collective of glass blowers in my home region that make decently priced, handmade glass bottles and will actually make you a new one for free if you break it and ship them the pieces ! I might get one at some point, but seeing how I manage to put a disturbing amount of dents in my metal bottles in record time, these are probably not right for me.