I ordinarily drink my coffee pure and simple - black, no sugar, none of that crap. But the taste of coffee changes radically when it's iced - whether this is due volatile oils evaporating as it sits or simply some result of our perception of taste, cold coffee tastes immensely bitter, and it loses much of the richness of flavor that it should have. As such, when I make iced coffee, I add various flavorings.
First the preparation of the coffee. I prefer it slightly strong, actually, as it seems that the 'coffee' taste is dulled by cooling. I also prefer a lighter roast - no matter how good that French roast or Viennese roast might be hot, the dark, bitter flavors are overwhelming in cold coffee. Also, don't bother with any fancy varietal coffees, as you'll lose all the subtle flavors in that Kona or Jamaican Blue Mountain.
Add quite a bit of cinnamon to the ground coffee - don't skimp, as the cinnamon's flavor doesn't come through terribly strongly. Add some cloves as well (they go wonderfully with coffee) but, since they seem to extract into water much more freely, go easy. Brew it, and while it's hot, pour it into a Thermos or whatever you intend to drink the coffee in. Add some sugar now (remember, cold coffee is bitter) - I add a sizable amount, but add until it tastes right. Stick that sucker in the fridge (if you put it in the Thermos, leave the top off. You're trying to cool the stuff down, remember?) and let it get ice cold. I'd also advise cleaning out the coffee pot quickly - while this stuff isn't as vile as 'flavored coffee' in terms of flavoring your coffee maker, you best play it safe when it comes to something as important as coffee.
This is good on hot days or when you need to take coffee somewhere that a hot drink might be inconvenient. It's just as caffeinaceous as real coffee (and thus much stronger than even the most highly caffeinated soft drinks) but it's also refreshing and the cinnamon and cloves help minimize the evolution of coffee breath. And it keeps for several days in the fridge, so I like to make several bottles at a time.