Some nailers can drive nails into concrete or steel; others are suitable only for wood. Larger nailers are best for heavy-duty carpentry such as framing. Smaller nailers are good for decorative carpentry such as crown molding.
#Drywall is a mainstay in home building materials. Learn all about the different types, here: http://www.diynetwork.com/how-to/rooms-and-spaces/walls-and-ceilings/all-about-the-different-types-of-drywall
I suspect there isn't a person in the world who hasn't had trouble trying to find a wall stud when hanging a picture, shelf, or TV mount. Most stud finders are inconsistent at best. In lieu of buying yet another tool, here are a few tips for finding a stud without any fancy equipment.