What kind of sweetener can I substitute for maple syrup in a quick bread?

But if you are looking at what you have on hand, then hardlikearmour's pointers on sugar make great sense. I might add that sometimes I will add a little Cointreau, Grand Marnier , or appropriate flavored liqueur if I am jut a bit short on syrup to make up the difference.

If you are in the market for really different options, then I would suggest sapa from Nudo-
http://www.nudo-italia.com/products/51

Honey would be my choice, too. But you could also consider pomegranate or mulberry grape molasses or even malt barley. which I would thin to the maple consistency.

Agave? If you just need to top off the maple syrup on hand, it would probably slip in unnoticed, It appears to have the same density/liquidity/specific gravity as maple. I even have one that is maple flavored. And if you are close to the amount needed, you may have enough. I find most quick bread sugar recommendations too sweet for me. If you reduce the amount of sweetener, then you'd want to fill in for the amount of liquid, though I can't tell you how much! Quick breads are flexible enough that you may be able to judge by the look of the batter.

I was just about to post honey, too. And it won't change your acid to baking soda ratio.

http://www.foodsubs.com/SyrupsHoney.html

http://www.foodsubs.com/Syrups.html
For sugar you would use 1 cup for every 3/4 cup maple syrup called for, then add 3 T water for every cup sugar used. If it's a recipe that calls for baking soda you'd also decrease the amount by 1/4 teaspoon per cup sugar used.