Whether you’re buying a boat for the first time, or it’s just been a long while - you might benefit from a refresher on what types of boat are out there. The boats that I’m going to cover here are mainly for day-use out on lakes and reservoirs. Anything bigger than that and you’re starting to get out of my league (for now). My wife grew up boating but I didn’t know much about any type of motor-driven boat until a couple of years ago. This overview will help you get a handle on what’s out there and what might fit your style and budget.
Outboard

This type of boat has an outboard motor, meaning that the entire motor and drive unit (propeller) is external to the boat and is attached to the back. You’ll find this most often used on fishing-type boats, but it’ll also appear on older water-ski boats. In addition, I see a lot of speed boats using this configuration. The benefits to an outboard boat are mainly in cost, and they’re a little simpler to maintain and operate than the others listed here. You can use this type of boat for wakeboarding and other towable sports, but if you really get into it, you’ll probably want to graduate into one of the other types. Do NOT wakesurf behind this boat, though, due to danger of getting too close to the propeller.
Sterndrive, or I/O (Inboard/Outboard)

This is identical to an outboard boat in terms of the drive unit, it is external to the boat and contains the propeller and pivots with the steering wheel to turn the boat. However, the engine is much larger and is inside the boat, at the stern, and is connected to the drive unit through the transom. These make great waterskiing and wakeboarding boats. You cannot wakesurf behind them, though, due to danger of getting too close to the propeller. These are going to cost you more than the outboard boats, but will generally be less expensive than the inboard boats listed below.
Inboard Direct Drive

Inboard boats have a fixed propeller, meaning it is on a shaft that does not allow the propeller to pivot. It simply spins and pushes the water straight back. There is a rudder affixed to the boat a few inches behind the propeller and the steering wheel pivots this rudder left and right to direct the flow of water and thus steer the boat. Inboard boats generally have a platform of some sort on the back of the boat. A direct drive inboard boat has the engine located almost directly in the center of the boat. These types of boats are for the die-hard water skier. The location of the engine in the center means that the boat will sit very flat on the water, and create little to no wake behind it, leaving it nice and smooth for the skier. In recent years, wake towers have been pretty common on these boats and they’re used more and more for wake boarding and wake surfing as well. It is a little bit harder to create a nice wake for boarding and surfing behind these boats, but possible with additional weight placed in the right spot and the assistance of such devices as the wedge on a Malibu boat. As soon as you cross over into the inboard boats, the cost goes up. Direct drives are less expensive than a V-drive boat, though, and can usually be used for all of the same things, you just have to be a little more creative if you want a large wake.
Inboard V-Drive

The V-drive is identical to the direct drive, except that it has the engine placed at the back of the boat, to add more weight there and help create a larger wake. This type of boat is designed for wakesurfing and wakeboarding. A water skier can also be happy behind this type of boat, but you’ll never be able to match the flatness of a wake created by a direct drive boat. V-drives are more expensive than direct drives.
Jet Boats
I don’t have an illustration of one, but I thought it would be good to include a description anyway. A jet boat is generally a fisherman’s boat. It is propelled by pulling water into the boat and forcing it out in a concentrated stream from the back of the boat via a ‘jet’. The boat is steered by pivoting this jet to direct the stream in different directions. The big advantage of this boat is that due to the absence of a propeller, it can be taken into very shallow water. This leads to it being used on a lot of rivers to get to places that no other boat would be able to. I don’t know how these rate in terms of cost to the other boats mentioned.