To vermiculite, or not?

Hi all.

I've been mostly lurking here, since right near the creation of the list.
I posted a couple of months back, announcing that I was about to set up
a plant-centered, CO2-injected 55gallon, and asked for some input.  This
would be my first real "plant tank".  Well, that tank is still not set up -
I've been busy with other stuff.  But now, I want/need to get it set up

Anyway, I'm deciding what to do for substrate.  I've been following all this
vermiculite discussion, and my question essentially boils down to this:
Of the following list of substrates, which is the "safest", and which is
likely to produce the "best" results:
	1) All gravel
	2) A Kelly-Pushak vermiculite/humus/gravel mix at the bottom, 
	   with plain gravel on top
	3) A mix of just gravel/vermiculite at the bottom, and plain gravel
	   on top.

While I realize that these have become somewhat religious issues on this
list, what I need is basic advice.  I would like my tank to be "successful",
meaning that it has good plant growth for at least a couple of years.  And
while I'd like to be able to be another useful data-point in
net.plant.research, I'd *much* rather be a success data-point than a failure

So, which should I do?

Davin Milun    Internet:  milun at cs_Buffalo.EDU
               Fax:       (716) 645-3464
               WWW:       http://www.cs.buffalo.edu/~milun/