I’m a big fan of young cherry. About anything will work well though, depending on how picky you and your guests are regarding “over-smoking.” Some people think hickory and esp. mesquite are overkill for something like this, and lighter fruitwoods are recommended because of it. I think that’s a matter of personal opinion really. I like apple as well.
I’d recommend covering breast with uncooked bacon to retain moisture if they don’t have any skin on them. Otherwise the smoke will really dry them out! Brining and/or injecting is recommended as well. You’ll have a more moist final product.
Good luck!
Joel