Don't you guys find that a black background absorbs alot of light? I once used black cardboard for a background on my 27gal. The moment I removed it (exposing the light coloured wall) the tank looked much brighter.  
 
Right now my background is a light blue but I'm thinking of switching to a darker blue. 
		
	
		
		
		
		
			
				__________________ 
				-Mason
			 
		
		
		
		
	
		
		
	
	
	 |