I've found (through years of trial and error):
Solid floors - connect
Floating floors - isolate
So, working down from the speaker:
For both floor types > Speaker > blu-tac > stand (omit blu-tac and stand for floorstanders)
Then, for solid floors > spikes > floor
For floating floors > spikes > spike shoes > solid plinth (granite tile in my case) > carpet > floor
If you have laminate or solid wood floors (in the floating instance), then a layer of carpet under the plinth can provide further isolation.
There may be oither ways of achieving the desired results, but on my particular floating floor the cavity under the floor wanted to play a huge part in the reproduction of bass, and not to good effect! By isolating as above it all cleaned up nicely.