Will say this, a speaker stand that rattles ruins your audio. Even if its just a little bit it makes a difference. And if its hollow that can lead to problems to: sound is just vibrations going through air. Those vibrations carry into the what the speakers are mounted on, hence the reason that a speaker in a better cabinet can sound better.
In the same way, I'd bet a speaker stand can make some difference. Not as much as good speakers make, but a stand thats solid, produces no vibrations and doesn't (therefor) allow the sound to run through it could make some difference. Again, as much difference as better speakers? No, but if you already have good speakers, it's not a bad idea to have some good stands. And if we are to assume that the stands making a difference is akin to the speaker wire making a difference, then I have to say: why does the room make a difference then? Why spend all that money on the walls being treated?
But we know the room makes a difference in the listening space. The stands are part of the room and incredibly prevalent to the speakers. I'd give the speaker stands then much more leverage than the wire.
Of course all this is assuming that you are playing at a high enough volume level that it'd actually affect the stands in the first place.