Never bothered to figure out cost factors; however, just a hunch that electric & propane would be cheaper than charcoal in the long run. Not really concerned with the issue. FWIW, I have been using cowboy charcoal; chunk charcoal that I get at Home Depot. Believe it is a little cheaper per bag than Kingsford and the claim is that its all natural, no additives. Seems as though I remember reading an article about how briquettes are manufactured and the additional additives used in the process. This is not to say that I wont grab some briquettes to use in the old Weber kettle when I want to grill some good steaks.
Woods:
Hickory for all the red meats. Everyones go to I suppose. Nothing better than hickory smoked baby backs or a quality steak.
Cherry Had to cut down a wild cherry tree a couple of years ago, I now have a lifetime supply. Use half cherry, half hickory for smoking pork butts and loins. The cherry adds a little sweetness to the finished bark.
Apple My go to for chicken and turkey. Do not use anything else. I was lucky enough to have a good day a field this fall and shot three rough grouse (I enjoy bird hunting). Did them in the Weber with some apple chips; outstanding!
Maple I have just begun using maple more often in place of hickory. Friend had to take down a sugar maple at his house awhile back. His payment for my assistance was a nice log of maple and several good I.P.As when we were done. The wood is now sufficiently dried to begin using.
Oak I have tons of oak available; however, it just does not do anything for me so I rarely use it.
Mesquite Throw some chips in with the hickory when using the smoker on pork. However, I find that I use mesquite less and less. No particular reason.
Herbs The wife has an herb garden (even though I seem to be the one doing all the maintenance on it, per her instructions of course). Really like grabbing a handful of thyme, sage, rosemary and marjoram, putting them in a foil pouch when I grill up some chicken on the gas grill.
I tried smoking peppers last summer. Results were terrible! Wasted a good bunch of habs and jalapenos. I could not control the heat in my half ass smoker which resulted in a charred mess. Too much direct heat underneath the racks imo. May give it another go next year with my trusty old Weber kettle and indirect heat.
I am on a mission to find the perfect new smoker for my Xmas present to myself. It must be portable, easy to store, two door model and reasonably priced (sorry, no $900 smoker for me). Cannot decide between propane (for convenience) or charcoal (purist).