Thanks for the responses.  I've rarely needed to use 'no' because I don't care
about the furniture, except my stereo speakers which I was able to stop one
of the cats from scratching on by gently removing his feet from them.  He
seemed to learn ok.

But a new stray cat that I adopted often goes places that I would like to let
the original cats continue to use, and it would be great to get him to stay
off of them, such as a table on the front porch.  They wont go near him
because he is aggressive, so when he takes over a place that was theirs,
they give it up and let him have it, not just at the time, but continuing.

The main thing I would like the aggressive one to understand 'no' about is
stalking and attacking the others (the males, that is), but I think he will
never obey about that, so I'm looking into Feliway as a solution.

-cr

I used the same technique with Cleo Carrington Smith.   Instead
of marbles I just clapped my hands.  I always say her name first,
to get her attention and then say "No!" in a firm voice.   It is very
important to make eye contact.   Sometimes we pick up the squirt
bottle when she ignores us, to reinforce the lesson  but we have
rarely had to spray her.  

Cats sometimes get over excited as you know and it is difficult
for them to comprehend you.   You need to stop the cat from what it
is doing then and divert its attention elsewhere.

Generally, if you respect your cat and have it's trust, it
will listen to you more often than not.  We are lucky to have
a very intelligent cat with a very good nature.

rachel