I smoke only with mesquite because I prefer it for flavor with beef & chicken and it's free while camping by the truckload. I don't like it for pork. I'm going to brine some Buck Board Bacon pork and ...
I have always had a preference for apple. You really can't get a better wood for wild game in my opinion. For pork I will occasionally use hickory. I have that you can get some great results from walnut and pecan which can be hard to come by but I have heard teh shells work just as well.