I know it sounds crazy, but a bidget would be nice to know...

You can easily spend $1000 on just the head unit, $1000 on just the front stage speakers, $1500 on an amp, and $700 on 1 woofer!

So, do you want to spend $5000 for the "audiophile" sound? $3500? $1500?

I would suggest starting with a good head unit that has the features you want...something with decent output voltage, and RCA outputs for front and rear (or front, rear, sub). Next decide on speakers. There are TONS of choices out there, from $100 to $800 a set. Aluminum cone, paper cone, silk tweeter, titanium tweeter, and many other choices. Simply put, take a favorite CD to a few stores, and listen to a variety of speakers.

While you may not want to draw attention to yourself with the car rattling at a stop light, as an audiophile, you will definately want a subwoofer. There is too much important musical information NOT to have one. Do you "need" 4 12s...probably not. A properly designed enclosure for a 10 or 12 should do the trick.
I very seriously doubt you will get significant quality out of just a head unit power. I would suggest additional amps. You dont have to have a ton of power, but it helps. Make sure to get realistic power ratings on the amps. An amp that claims to make 1000 watts, but only has a single 20 amp fuse on the side...NOT gonna happen.

A good head unit, a good set of front speakers, a 4-channel amp, and a woofer, and yo should be well on your way.
Places that I might suggest: Most of the Hi Fi Buys installers are very good. Look at Traffic Jams in Buford, and CarTunes in Roswell. There are several great shops/installers around....

I hope that helped more than it confused you...

John