I've got a WSM (vertical smoker) with similar design.
I'm really happy - if I set the fire up right I can get 12 hours out of it easy without needing to refill. Thats using heat beads, charcoal I find I need to replenish after about 8hrs.
I'm using apple wood for smokewood at the moment as I got a load of it for free. The only stuff I've seen in chunk form at BBQ's galore is hickory, all the rest seems to come as tiny chips which you need to replenish regularly.
So far I've done chickens, baby back ribs, spare ribs, pork shoulder (Boston Butt), ABT's, sausages, chillis and salt in the smoker. I may do a beef brisket next Saturday (10-12hr smoke).
Smoking some rock salt might sound crazy, but it makes a great seasoning for any dishes where you want a very subtle smoke-like flavour added.
edit - One quick question - how are you maintaining a nice low smoking temp (100-120C) in there without a water pan or similar? Are you just using a small fire and replenishing often?