If you are a gearhead, or are any type of person who thinks of a car as far more than just a means to an end (that end being transportation), then you probably have already asked yourself this question. If not, think about it for a while. Do you really not care much about the four wheeled machine that is going to be taking you from home to work or school, as long as it works? If that is you, then the idea of what to get sounds pretty simple. Unfortunately for you, that assumption is quite wrong.
People who care about cars usually find themselves in a niche. Cars, trucks, SUVs, Vans, Crossovers, etc. Additionally, they more often than not can specialize it even more, such as European cars, Asian imports, or American cars. Within these bounds comes the fine-tuning for preferences in everything from company loyalty to horsepower.
As a person who doesn't really care so much, you will have to decide what you want in a vehicle instead of all that. For example, if all you care about is fuel economy, a small "city car" would work well for you. This is where reality sets in though. If you intend on being rational, more questions must develop. City cars get great mileage, are cheap to insure, and are easy to drive, but lack in performance, road safety, and practicality, to name a few. Buying a car means you have to branch out whether you like it or not. Here's a general guide to car classification for you to get a basic idea of what kinds of cars are available to you. Yes, there are bad cars out there, but there aren't really any "bad" classes. Every person has different needs and wants.