I use 2 parts apple juice to 1 part beer. Put in the fridge over night, with onion slices, smashed garlic cloves, whole jalapenos, and black peppercorns to soak. Next day when I smoke then foil, use to braise.
After they're done, drain the juices from the foil, and mix in to my BBQ sauce. DON'T WASTE THE JUICE!!!!! Especially after pulling apart a butt. Mix the juice with vinegar from pickled jalapenos, and use as a finishing sauce for pulled pork.
The last time I smoked ribs, I used a combination of Dr Pepper, apple juice, rum, and some apple cide vinegar for my braising fluid and it came out great. I had read about the Dr Pepper on here awhile back and decided to try it.