There are three basic choices when it comes to swimming pool construction today concrete, fiberglass and vinyl. Concrete also known as Shotcrete or Gunite construction is typically the most expensive and also the most customizable and longest lasting form of construction today. A concrete pool can be built in almost ant shape you mat desire looking for a star shape or maybe you need a custom shape to go around a natural obstacle well with concrete this is not a problem.
Fiberglass pools are probably the most popular type of in ground pools on the market today they are much less expensive than a concrete pool and require much less time to install. Fiberglass pools are made of site and are delivered in one piece to your location typically an in ground fiberglass pool can be installed in one day. It will take more time to set up the filter, heater and construct the coping around the pool but the overall construction time frame is far less than with a custom concert pool it is not impossible to have a fiberglass pool installed, the coping made and landscaped an in use in a weeks time.
The third type of in ground pool is a vinyl pool typically a steel shell that is the form of the pool is installed in the ground and a vinyl blanket or covering is spread over the steel form creating the pool. These types of pools have been on the decline with the advent of the one piece fiberglass pools but some advantages of the vinyl pool are size and cost typically a vinyl pool is larger than a fiberglass pool the drawbacks are the vinyl liner can be punctured causing a leak in the pool the leak can be patched once you find the leak.
This is just the basics in what is available in todays market in pools and hot tubs you may want to consider a landscape architect when designing your pool area you may also want to visit a home show to see what is best for your needs.