Everything you want and nothing more.
Here's a counter-opinion to Sawtoothme. I *love* this stuff. Most sports drinks are too sweet (too much sucrose and high-fructose corn syrup), too flavored, and (particularly annoying to me) too acidic. Once upon a time, I went too far in the opposite direction, and bought a tub of pure maltodextrin. It had no flavor at all, and was almost unpalatable. This stuff is perfect. It contains pretty much just long(ish) chain carbohydrates and electrolytes. The flavoring is very slight, and the sweeteners almost unnoticeable. Just enough to make you enjoy swigging it. I've used it in races time and time again, and I swear by the stuff. In longer races (>2 hours) I'll typically use something with some protein in it. I like Hammer Perpetuem. The nice thing with the mild flavoring is that you can blend your own magic potion without creating something undrinkable.