Quote Originally Posted by redrhodie View Post
I like it to be right at the floor, that way I get gravity helping lock the pump onto the stem.
I like it to be at the top and I think that's actually where most people pump. You get the straightest run from the hose, so you're less likely to be fighting that resistance. But maybe it's just a hold-over from pumps without latches, like the Silca pump, where pumping with the valve at the top allowed you to hold it until a good seal was established.

Either way, top or bottom, probably minimizes the chance of damaging the valve stem, because you have a clean push-pull to put the pump head on and take it off.