I like seasoned (at least a year old) cherry "wheels", quartered, and soaked in clean water. This tends to burn cleaner and does not seem to over darken meat like "green" cherry seems to, while still giving the flavor that we love. Make sure you get rid of as much bark as possible...whatever the wood. I will usually add my 1/4's to a hot pit on top of a good fire of lump a few pieces at a time.
I also make sure that things are burning completely before choking the pit down to take a nap. Cherry is awsome, but you have to be careful not to over smoke. Like anything that takes work--results can be amazing!