speaker/stand, couple or isolate?

You want to do two contradictory things:
Minimize the contact area the speaker cabinet has with the floor. This doesn't have to be extreme, but not resting the entire cabinet on the floor is bad.

Minimize the amount the speaker moves in space. The force a woofer has on the cabinet is significant. Sometimes adding weight to monitors can significantly improve clarity and bass.

@avanti1960   Thanks and my apologies.
Currently my speakers are on a ceramic tile floor that's on an underlying concrete basement floor. Cheers.

Now what about open topped stands, the kind of stand that, for instance, Harbeths tend to be put on, where there are only four points of contact to begin with, at the corners?  Those stands are made of either metal or wood, so there's another variable...

I experimented with putting a small amount of Blue Tack on the corners between the speakers and the stands and then switched to using the 2"x2"x1" square pads made-up with a layer of cork sandwiched between two layers of rubber. The speaker/stands are on spikes on top of Herbies cone/spike decoupling gliders. The floor is suspended hardwood above full basement. I use these rubber/cork pads under a subwoofer in my other system and electronics with good results.
Obviously an A/B test in realtime was not an option but I played the same tracks at the same volume using those configurations. All I could tell was if I listened closely, the bass notes seemed, and I underscore seemed, a tad better defined. In my case, the speakers weigh roughly 30 lbs. each and the stands weigh about the same filled with rice. The difference might be more noticeable when using smaller/lighter speakers.
Anyway, I think its something worth experimenting with standmount speakers but I wouldn’t expect as dramatic as a difference when compared with how the speaker/stand interacts with the floor, at least this was true in my situation.
Thank you all for your input.

Isolate unless you like the way your floor sounds.   If you notice any vibrations in your room, even just a little, if you jump up and down, your floor is capable of comtributing to the sound. 

If your floor is the concrete foundation at ground level, then no problem.