I would use something like 3/4" limestone. 
 
Looks good, settles really good for walking on, and isn't going to break the bank (or your back!).
		 
		
		
		
		
		
		
			
				__________________ 
				"Wake up, Luigi! The only time plumbers sleep on the job is when we're working by the hour."
			 
		
		
		
		
	 |