Screwdrivers: There are all kinds of weird screw heads. The basic types of screwdrivers are, straight blade or regular, Phillips, Allen and Torx. You should have four or five different sizes from small to large. When you select a screwdriver for a job, the blade must fit the slot securely with no slop and it must fit with no overhang side to side. This will greatly reduce the chances of destroying the screw slot. You should have three sizes of Phillips screwdrivers a #1, which is a small Phillips, a #2 which is a medium size and most often used and a #3 which is a large Phillips. Pozi-drive screwdrivers look a lot like a Phillips, but are not interchangeable. The patters are different and using a Phillips screwdriver on a Pozi-drive screw will damage the screw and vice-versa. Four lines pointing out from the center of the screw head can identify a Pozi-drive screw. Torx drivers come in sizes from #5 to #55 with #15 the most often used.
		Ratchets and Sockets: The three most common size of ratchets are 1/4", 3/8" and 1/2" drive with the most common being 3/8" drive. 1/4" drive is for lighter duty work while 1/2" drive is for heavier jobs. A fine tooth ratchet is preferable because you will get more turns per swing than a course tooth ratchet. I would not recommend a ratchet with a knurled handle. One with a contoured handle is much more comfortable and ergonomically efficient. Sockets come in many shapes and sizes, in both metric and SAE (fractional). In 3/8" drive a good range in SAE is 3/8" to 3/4" and metric 8mm to 19mm. Sockets come in deep and shallow styles. The deep sockets are good when you are taking a nut off a stud for example. You will need both styles in your toolbox. In 1/4" drive, a good range in SAE is 1/4" to 9/16" and in metric 4mm to 14mm. In 1/2" drive, 1/2" to 1 1/4" and in metric 13mm to 32mm. You can get sockets in hex (6-point) or double hex (12-point) styles. Sockets below 10mm will use 1/4" drive handles. 3/8" drive goes from 10mm up to 19mm. 1/2" drive goes from 10 up to 36mm. A pair of spark plug sockets is a must if you want to tune up a car. A good spark plug socket has a rubber insert to hold the spark plug from falling out. There are two sizes: 5/8" and 13/16". Universal joints allow the use of a socket in areas where you can't get straight on with a regular socket. Extensions are used to extend the reach of a socket. A good range of extensions is 1" to 12". Both of these are a must. Flex sockets are nice to have. They are similar to a universal joint but have a regular socket on one end. They are good for very tight situations The handles for these sockets come in all kinds of shapes, sizes, and styles. T-Handles are handy, as are rachet handles.Just pick the ones you like. Socket extensions come in all sizes from 1 1/2" long on up. Get several. You can hook them together to get any length extension you want. There are many other types of specialty sockets.
		Wrenches: Wrenches come in lots of types and sizes. The most common wrenches are open-end, box and combination wrenches. Open-end wrenches have ends that are, well, open. These are for those jobs where a box wrench will not fit. A box wrench has no open end and fits completely around the fastener. The box wrench is preferable to an open-end wrench because it will grip the fastener on all six sides. A combination wrench is a combination of both, box on one end and open on the other. This is the most useful and eliminates the need for two sets of wrenches. A good range of combination wrenches is 1/4" to 7/8" and 8mm to 22mm. Wrenches come in short styles for tight areas, standard length and long when extra leverage is needed.
		Crescent Wrench: An adjustable wrench is also handy to have. These have two jaws that are adjusted with a screw mechanism that open and close the jaws parallel to each other. Have it both in metric and SAE adjustable wrenches. One is a 6-inch adjustable and the other is a 300mm adjustable.
		Hammers: Hammers also come in many shapes and sizes. The most common hammer used in automotive work is the ball-peen hammer. A ball-peen hammer has a regular striking face on one end and a rounded "ball" on the other end. Dead blow hammers have a hollow head filled with shot to prevent rebound and direct more force to the object struck. Hammers are sized by weight, from an 8 ounce tapping hammer to a 20-pound sledge.
		Pliers and Cutters: Nothing beats a pair of plain slip joint pliers. The ones with soft plastic grips, are more comfortable. Water pump of Channel lock pliers are also a must have. These are like slip joint pliers except they have angled jaws and several different grooves for adjusting the jaw size. A large and small pair is good for your toolbox. Needle nose pliers are a pair of pliers that have two thin jaws that come to a point. Keep a large and small pair in your toolbox. A good pair of wire cutters is a necessary item. For the home mechanics a large and small pair will do. A good pair of terminal pliers is handy to have. These will strip and cut wire and crimp solderless terminals. You can get a pair in a kit with an assortment of solderless terminals at any auto parts store. Vice-Grip types are very useful. If you only have one make it a medium sized Vice-Grip.
		Impact Driver: The Impact Driver is a must have tool. Impact Drivers come in both 3/8" and 1/2" drives. You can use screw driver bits or sockets with them. To use an impact driver first select the right size of bit, then put it on the driver and onto the screw. Turn the body of the driver in the direction you want to turn. This "cocks" the tool, so to speak. Than, hit it on the end, with a hammer, good and hard, to come off. Remember to back up the part. If the part with the screw in it is not strong enough to take the hammer blow, it will break.
		Miscellaneous Tools: Some other tools to round off your toolbox are: A Tire Pressure Gauge. A tire gauge should measure up to 50 psi. A magnetic pick up tool is a good thing to have. This has either a flexible or telescoping shaft with a magnet on the end to pick up those nuts, bolts and tools that have fallen into places that you can't get your hand into. Punches and chisels are nice to have for general use. You can get a nice set with several different sizes. Files are good to have for general de-burring work. A decent digital Volt-Ohm meter is good to have for testing circuits and sensors. A 12-volt test light for checking continuity and power in a circuit is a must. Masking tape and a felt tip-marking pen for labeling vacuum lines and wires is very handy to have.