There are many other things you can use in your hookah base instead of water. Most of these will have to be mixed with some water though because most other bases will be to strong or will foam when you pull through it. If you are going to use a carbonated beverage such as soda or an energy drink, it is based to let it go flat first so you may use more of it without it foaming or fizzing up. Alcoholic beverages can also be good bases. Just think of your favorite flavor of martini, and can be recreated with some creativity and strong alcohol such as Everclear, vodka, or rum. It takes a while to get the mixture right so its not so strong, but with an appropriate amount of water, it can taste great! Another good option is fruit juice. Generally stronger citrus juices work well because they can be tasted through the hookah base. Yet again, this will take a proper mixture of water to prevent it from foaming up.

Whatever base you decide to try, it will take some experimenting. But after a while, you may find a combination to die for!