Nobody is going to answer your question without more details. The question you ask is a bit like asking "what kind of dog should I get?" Depends on your personal preferences, what kind of environment you're keeping it in, etc.
So, what kind of car do you have? Do you have already have some speakers in there you want to replace? to add to? You already have amps you're going to use to drive the speakers?
Then, about how much money do you have to spend?
Less importantly, what kind of music do you listen to? Also, what sounds good to you musicwise: for example, do you like a loud, thumpy bass, or are vocals really important to you?
There are a number of guys in this forum who could give you some advice, but you need to ask a more focused question.