Think the consensus these days is AAdvantage miles are worth about $0.015 per mile. I use miles for two things these days: flying my mom across country to watch the kids when I have long trips and F class flights. When she comes out from SAN, air fare is usually in the $400 range. So, I find value in spending 22,500 or 25,000 miles in flying her back and forth.
A bigger value is in F class tickets. F class to CA from here is about $1100 round trip. In award miles, thats $750, so a real savings.
Bear in mind, if you have a ton of miles, you've got miles to burn you've got a lot of free dollars on hand.