If you're interested in a midgate enclosure and would like it soon, PM KodiakZ; he's built several midgate integrated boxes that look great, are well built and he knows what he's doing with subs.
As for source units, it's more a matter of what features you want than a brand being better or worse currently. They all use similar d/a converters, output circuitry that seems to be around 20-25W per channel, many play mp3 files, some will do wma's, several have pretty little dolphins mating on screen while you drive while others have stuck to a classic approach to their appearance. You can easily find a two or three way crossover built into many heads, a few offer EQ's that are actually useful, most have a dedicated non-fading sub output and on and on........
As for amps, you can't get any better than Linear Power, Zapco and US Amps. McIntosh makes really attractive amps, but they are HUGE and costly. If you like old equipment, check out Adcom's car amps from several years ago and the now obsolete a/d/s powerplates.
Speakers are totally a matter of budget, and will make the absolute biggest difference in your system. You've got high end all the way to swap meet prices, it is just a matter of what you want to spend. Please DO NOT buy any speaker set without listening to them first, preferably in a car and not on a demo board. If something sounds good to you, go with it. If someone says "this one is better, you don't want those" you can give him/her a good chance to explain exactly why they are better, and a chance to prove it. If they can't, head to the next shop until you find an honest one.
Give us some more details about what you're looking for, as I'm sure you'll get plenty of opinions from the forum.