I have several stud finders (actually edge finders) made by Zircon. The one I managed to find is a Studsensor i65. The LCD display is much easier to use than a row of LEDs type. Buy several so that when the neighbor borrows yours and doesn't return it, you are still functional.
As someone mentioned previously, there can be problems dealing with foil backed insulation if it is improperly installed. There is suppose to be a small air gap between the foil and the back of the drywall. That makes it easy for the stud finder to see the change in density. However, if someone installed the insulation over the studs, and then nailed the drywall over the edges, the aluminum will shield the stud and the stud finder is not going to work. I've seen this exactly once on an owner built home, so I wouldn't worry about it much.
Hint: Heavy tools hit the ground rather hard. I suggest you store them on shelves, where a crash landing isn't as likely.