I carry a 2L platapus hoser bladder and then a 1L Platapus soft bottle for mixing energy drink. I use the 2L Playtapus gravity feed water filter system, so if I stop for lunch near water it makes it really easy to fill up, and just use the water directly out of the filter bag to make my meals.
If push comes to shove, I have the ability to carry 5L of water between the 2L dirty bladder, 2L hydration bladder, and 1L softbottle.