How much do you want to spend?
What kind of music do you listen to?
I know that the type of posts that you are looking for are ones where people will tell you exactly what you should get, but to be 100% honest, you really can't listen to any ones advise on this matter.
The reason is because its your ears that are going to be sitting in the car listening to the speakers, so the only way for you to find out what the best speakers are is to go to your local audio shop and listen to them. Also, it's hard to suggest a brand to you because just about every brand out there has at least one high end, good sounding speaker model. Even the crappy brands usually have some thing in there line up that sounds really good.
With all that being said, I will at least tell you what kind of stuff I chose for my car to give you a starting point.
For speakers, I went with MB quart's over any of the competition. MB Quart is generally considered to be one of the top brands in terms of sound quality, but some people don't like them because they think that the high end frequency's that they reproduce are a little harsh. I personally really like the way the highs sound in the Celica, a lot of the harshness is going to be dictated by the tweeter placment, and the Celica happens to have pretty good component tweeter placement from the factory. The best thing that I liked about the MB Quarts compared to the other high end speakers that I listend to was the way that they sounded when cranked up loud. I thought that they faithfully reproduced high volume sound better than any other speaker I listened to.
For amps, I would suggest going with a high quality amp over a cheap high out put amp. What I mean is, don't just judge them by their level of power. I would recommend looking into Alpine and Eclipse.
If you want to add a sub to your car for a little extra bass, I would recommend looking into Eclipse or JL audio subs. I would also recommend getting a sealed box instead of a ported box. You can put a lot more power thrue a sub that is in a orted enclosure, which means you will get a lot more volume out of it, but sealed enclosures sound so much better to me. Again, that's just my opinion.
I'm not 100% sure, but I think that I've seen TimePort posting on this forum? If he does, you might want to ask him about this stuff. He is pretty knowledgeable when it comes to stereo.