Q-logic kick panels or door pods by Audiowizard. The Q-forms only fit a 5.25" and a tweet, but will suffice just fine. The door pods Audiowizard makes can hold just about anything you want up to 6.5", he will make it to fit what you want. That takes care of the front stage.
For head unit, I would recommend either lower model Alpine or Pioneer, JVC, and other quality brands, or go with the Delco radio's out of mid/late 90's Chevy trucks or out of f-body's. If you go the delco route then you will need some quality line output converters (for use with an amp), they can be found at
www.davidnavone.com (under adaptors).
Rear speakers I would say just go get some 6x9's and the adaptors to make them fit. For brands, go to a car audio shop and demo different brands and pick the ones you like best.
You can power all the main speakers from the headunit or get an amp to power them (best option, but more $$). For amp, look into Kicker, Rockford Fosgate, MTX, Hifonics, Memphis and the list goes on.
For sub, a lot of people have many good things to say about Alpine's Type R. I've never heard one before, but haven't heard any bad things about them and they can be had for cheap. A single 10" or 12" will be perfect. JL's W3 subs are very good and aren't expensive, Kicker Comp are good as well. The list goes on for subs as well.
You have A LOT of choices to make, I would suggest just looking around and getting an idea of what you want and how much you want to spend. Don't rush it, listen to other peoples stereo's and see how it sounds and such.
You best bang/$$ now would be to get some good main speakers and power them off the head unit and then get a sub and amp. Then later on if you want more, you can add an amp to the main speakers.
Thanks Bradley!!!! 
