Okay, I have just looked at some magazine that my friend let me borrow that goes over all of the walls in the game.  Some of the choices for good stallers are awful.  Here are all of the ones they listed:
 
Chansey
Lickitung
Mewtwo
Mr. Mime
Onix
Snorlax(but they said this one was an awful choice)
Zapdos
 
Here are the ones I agree with.
 
Chansey:  Man, does this card rule!  120 HP is perfect for a wall as is scrunch!  Double edge lets you take 2 prizes for the price of one and it is perfect for the late game!
 
Onix:  Though common, this guy is very overlooked.  90 Hit Points is great for a staller, as is harden.  This is a great "poor man's" staller.
 
Lickitung:  Here is another "poor man's" staller like onix, but this guy really kicks major @$$!  He is the only one with the ability to stall and do damage at the same time!
 
Snorlax:  They're right, snorlax is a bad staller.  He is a much better attacker than a staller for his ability to do 30+paralize and not take status changes.
 
And here are the ones I disagree with:
 
Mewtwo(base set):  Man, does this card bite.  it's psychic attack really sucks and its barrier attack wastes energy (that you SHOULD be putting on your benched pokés at the time).  But, in the magazine, they mention "this card rules because he is the cornerstone of the famous mullie-mew deck--just keep using barrier and make the enemy run out of cards!"  Well I've got news for ya--THAT IS AN ILLEGAL DECK!
 
Zapdos:  Sure he is a good staller against haymakers but you really cant gaurentee that you will fight one every time.  This card is nothing more than trash.
 
As for mister mime, he is only a good staller when you have an alakazam and a chansey/tentacool out too.  when you have that combo running he is a PERFECT staller but you dont have much of a chance of getting all three cards out.  I'd rather use mime as an attacker.
 
Here are ones they didn't mention:
 
Grimer:  Don't let 50hp fool you - Grimer is an exelent staller.  for just one energy he can prevent all twenty of ten attacks and nasty goo paralizes!  excelent!
 
Ryhorn:  Rhydon is weak and energy intensive but rhyhorn is a good pokemon.  70 hp is good and so is leer.
 
If there are any I missed e-mail me at tymy1223@aol.com or tymy1223@directweb.com .
 
-Tyler C.