I believe you can make an argument for any club in your bag depending on the golfer, course, etc., but with that said keep in mind a majority of your scoring comes from 150 yards and in. I believe those yardages and clubs are often overlooked because everyone wants to bomb a drive down the middle or execute two great shots to hit a par five in two giving them the opportunity for that elusive eagle putt.
In my conversations with golfers I have found that most people will say the Driver for a few reasons. You hit it 12-15 times a round depending on the course layout, and arguable the farther you hit it the better chance you have to hit a green. There’s also a big emphasis on hitting the fairway to leave you with a better approach shot into the green.
You can also argue that your fairway wood or hybrid are the most important because you utilize them on par 3’s, 4’s and par 5’s based on the yardages and want to be able to reach the green or get it as close to the green as possible.
Some will also say the most important club in your bag would be a wedge. Yes, you have more than one wedge; however when you miss a green the proximity to the hole on that chip or pitch is important to save your par. You also want that comfortable yardage to lay up in order to hit it close to the hole. The wedge also has to be a very versatile club because you are hitting it from many different conditions around the green.
I want you to take a look at what club you think is the most important to your game and make sure you are getting the most out of that club. You also may find that your initial thought is different after reevaluating your game.