Well, if you are happy it seems like its a personal preference between the dancing banana and the disco monkey, but when you are really really excited, both can be used.
Banana:
	Quote:
	
	
		
			
				OMG S-Squared is having another BBQ    
			
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 Disco:
	Quote:
	
	
		
			
				Just got new coilovers for my ride  
			
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 Monkey:
	Quote:
	
	
		
			
				I would like to give a   to the Durango driver who cut me off this morning on my way to work.
			
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I don't think the angry monkey would make a whole lot of sense in a post with a dancing banana, unless something really wierd happened like...
	Quote:
	
	
		
			
				I just found out my gf is a hooker   
 
 
 
 
 
 
But so is her roommate  
			
		 | 
	
	
 Other icons:
huh:
	Quote:
	
	
		| 
			
				Hi, I'm a noob.  Can someone tell me where to I can install my boost fluid gague?
			
		 | 
	
	
 
Furious:
	Quote:
	
	
		
			
				I hate FedEx, they lost my package again.  For the fifth time this week!!!!!  
			
		 | 
	
	
 Alien:
I don't think I've ever used the alien icon. I have no idea what that is supposed to mean.  You get to make up your own with that one.
EDIT: Damn, sperry beat me to it...