I agree on the CDT rec. I have CDT components in all of my vehicles. Go to
WoofersEtc.com - The Online Car Audio Super Store, The largest selection at the lowest prices! You can pick up a pair for $99. They will blow away anything in that price range. There are plenty of other really good brands too like Focal, Hybrid, etc. But for the money, I think CDT is the best. I only put components in the front stage. I think the extra hassle of installation is worth it. For rear fill, there are different opinions. Some people say that it doesn't matter at all. A lot of high-end installations will completely do away with the rear stage. If you do opt for rear fill then a high quality set of coax would be fine.
While I agree that listening to speakers in person is great, sometimes it's difficult to do. Going down to your local box store and listening to a wall of speakers doesn't really tell you much about how they will sound in YOUR vehicle. There are so many factors. A better independent shop will give you a better idea. They at least will probably have them set up properly. The best would be to listen to them installed in a vehicle. That will give you an accurate representation.