Oh wow!! This could be a long thread. You should get quit a few responses.
There are so many things you can do.
Myself, I like sweet things. Juices of any sort. I've used pineapple, orange, apple, Dr.pepper, Sprite, cherry. ect..
I've even heard of others on here using cherry cool-aid.
Just mix up something you like and go for it. Experiment a little.