For the booze, you could go with something in the chocolate family, such as creme de cacao or Godiva liqueur. In the fruit family, in addition to some of the above recs, I'd consider kirsch. Although cherry not berry, the fruit flavor isn't overwhelming and the brandy could be preferable to a sweet, syrupy liqueur. I like Chambord, but find in baked goods it can be overdone, so use sparingly or mixed with a spirit. I have a cranberry-pistachio biscotti I make at Christmas, and the recipe calls for plumping the cranberries in vodka, then pouring the berries and the soaking liquid into the batter. I've adapted to a half vodka/half Chambord mixture and enjoy the balance.
One more quick Chambord story, before I stray too far off topic: My husband and I have a running gag of "_____ is the new Chambord." At one time we somehow possessed three bottles of Chambord, so whenever we think we're out of something, "replace" it, then discover we weren't depleted, it becomes the new Chambord.