I run a cabinet shop and we use the 18ga more than anything. In the shop, the nail only has to hold the joint until the glue dries. When putting up trim, we use the 16ga because there is no glue involved. As Jim stated, the 18ga sometimes follows the grain in the wood, especially with harder woods like oak, hickory, and sometimes maple. We use a 23ga pinner to nail up raised panel doors, again because it only has to hold the joint until the glue dries. We mostly use the 1 1/4" nails in the 18ga, 1 3/4" (sometimes 2") in the 16ga and 1/2" in the 23ga. We also use a 1/4" narrow crown stapler for the backs of the cabinets and normally use 1/2" staples in it.