I used chips for many years and began using just chunks 6 years ago with great success. I found the chips gave a good, but short blast of smoke no matter how long I soaked them. Using chunks, I don't soak them but place in aluminum foil with some openings and place on the coals. They will produce that way for a few hours giving off a low amount of smoke which I like. I am fortunate to have a good source for a large variety of fresh cut wood I that can make my own chunks from. I usually use two or three chunks 11/2 to 2 inches thick and about 3 inches long at any one time. Like what was mentioned above I normally mix woods when smoking, or just go straight such as with mesquite or apple. My main mix wood is oak which I feel gives meat a nice rich taste. For our taste buds, straight hickory needs to be used in moderation as it can over power foods and spices. I also feel chunks give off a more flavorful smoke, but since I use freshly cut wood this may be the cause.
Also, I only use smoke for about 2-3 hours on a butt and turkey, 1 hour on ribs, and about 1-2 hours on a whole chicken. We only like a bit of smoke on our Q.