I have the RedHead Ripcord. Its small/medium size, has a hydration pack and can hold alot with its bungee cords on the back (If needed).
Plus is $39
I've had mine for 2 years and it's still holding very strong.
http://www.basspro.com/webapp/wcs/stores/servlet/Product_10151_-1_10001_80031_400008012_400000000_400008000_400-8-12