So like many adult males, I am a tool snob. My mom thinks I spend too much on tools, given that I am a college student, but I don't buy them as frequently as she thinks I do. (Also, I don't go to the hardware store to sober up anymore. The novelty wore off.) Here's a list of everything I consider essential:
1: 16 ounce claw hammer. The standard size hammer, can be used for just about anything. It can do just about anything a ball pein hammer will, and those things it can't do don't concern me.
2: Screwdriver set. I prefer an assortment of the good old fashioned one piece screwdrivers, as opposed to the combination Phillips/slotted screwdrivers. The shafts are thinner, and thus able to fit into smaller holes. Also, there aren't any pieces to lose.
3: Measuring tape. Can't measure anything without it.
4: Cordless drill driver. The drill driver is distinct from a drill in that while it is excellent for drilling holes, it is much better suited to driving screws than a conventional drill is. The main difference between the two is in the clutch. In a conventional drill, the chuck is geared directly to the motor. In a drill driver, there is a clutch between the chuck and the motor, which disengages when the back torque from the chuck exceeds a set amount. This makes the tool much better for driving screws, as it is easier to avoid overdriving the screw.
5: Backsaw. A crosscut saw specially designed for use with mitre boxes, I prefer them to standard crosscut saws for their compact size, and the spine on the top of the blade, which gives them greater rigidity.
6: Socket wrench set. A ratchet, when it can fit onto the fastener, is usually faster and easier than a combination wrench.
7: Combination wrench set. Because a socket wrench doesn't work for everything.
8: Large crescent wrench. The small ones slip easily and round off the sides of the fastener, but once you start dealing with 3/4in+ fasteners and fittings, that happens less, and a crescent wrench is easier to carry than several large combination wrenches.
9: Levels and Squares. A torpedo level is sufficient for most tasks. Each type of square has it's best applications, some are more likely to be used than others, so I'll list them in order of usefulness: Try square- good for just about all small work. Framing square- good for larger work. Speed square- kind of a cross between a try square and a framing square. Combination square- a rickety, somewhat inaccurate mechanical affair, it's one strength, in my opinion is it's ability to fit into small spaces. Drywall square- good for layout work on drywall, plywood, and other such materials.
10: Allen wrenches. I prefer the all-in-ones where the individual keys fold into the handle. They're much more ergonomic than individual keys.
11: Utility knife. I put it here because you can usually use something else in a pinch.
12: Punches, Scratch awls, countersinks etc. They make life so much easier. Just try drilling a hole in metal or concrete without punching it first. Counter sinks are for hiding nails in the woodwork.
13: I'm Triskaidekaphobic. So there is no 13.
14: Tin snips. There's some things even a utility knife won't cut.
15: Files, rasps, etc. For whenever you need to remove a minute amount of material.
16: Pop rivet tool. Pop rivets are quite useful for metal work. They are aesthetically more pleasing than screws, and can be used in closer quarters.
17: Blacksmith hammer. Sometimes a claw hammer doesn't cut it. There are several types of large hammer; my favorite is the blacksmith hammer. It has one flat face, while the other end of the head is pointed, making it more versatile than other large hammers. It's great for driving a masonry chisel.
18: Masonry chisel. All you really need to make holes in, or to knock down concrete block walls, though it might take you a while. I prefer the single bevel variety.
19: Circular saw. I'm right handed, but prefer left handed circular saws. A right handed circular saw is set up with the motor on the left, with the blade on the right, with the result that you can't see a damn thing. If you're willing to spend some extra $$, go for a worm drive saw. They're heavier, and louder, but considerably more powerful.