If you're using a sweetener to cut the bitterness (rather than to add sweetness), then you may enjoy cold-brewed coffee. Cold water is far less effective than hot water at extracting tannins from coffee grounds, which are the primary source of the bitterness in coffee. So cold-brewed coffee tends to be naturally less bitter, as a result.

Bonus points in that it's less acidic, as well. And in case anyone else is as oblivious as I originally was, "cold-brewed" doesn't actually have to equate to cold coffee. You end up with a coffee concentrate, which you dilute with water to preference (taste, caffeine content, etc). You can dilute a cup with boiling water to get a hot cup of (non-bitter) coffee just as easily as you can dilute it with ice water for a cold, ice coffee.