You have a budget, that is good but you don't have a game plan and that is what you need. Someone pointed out that one of the guru's may suggest something. I don't profess to be one of these people, but I will always give solid info.
(1) determine what level of system you want - where do you want to go with your system?
(2) Sacrifice is better than compromise - it cost twice as much to buy the wrong things
(3) the cd player is the single most important purchase - it will make or break the sound quality and capabilities of your system - see point 1 and point 2.
(4) the front speakers are the next most important purchase - buy what sounds best to you.
(5) vehicle type - can't get speakers until we know a vehicle
(6) type of music listened to - what works with what
(7) not all subs are created equal and everyone will have there favorite - get ready for my sub is the best because, everyone will post.
(8) amplifiers are not called wattlifiers - throw spec's out the window
(9) do research into the suggestions
(10) warranty is extremely important, support the local specialty retailer, they are the ones that need and appreciate your business, if you need help, chances are that they are the ones that will bail you out (if we can't help you). Specialty lines are available at specialty retailers, they are not built to be cheap, they are built to sound good and have superior capabilities.
This said, for now I will only offer one choice for you until you respond to the above. I'm sure most senior members will agree. For the most important purchase I will recommend a Eclipse 5volt cd player, if you need MP3 (hope not) then wait until the new ones are out very soon, if not, but the Eclipse CD5423, this is where your system starts. Why, it is expandable for full expansion to multiple amplifiers, initially front - rear - sub. It has 5volt non clipping low impedance preouts. The higher the voltage the easier it is for an amp to make power. Non clipping means that in a fully amplified system, if the gains are set proper on the amps, the volume level will play to max with no distortion - very few cd players are capable of this. Low impedance means improved sound quality, the tradeoff here is it takes more $ to keep noise from entering the signal, this is why most cd players have a higher impedance - they don't want to spend the $. Theft deterrence - replace free of charge in the first year if stolen, must be bought from and installed buy an authorized dealer. 3 year warranty when installed by authorized dealer - no $ to pay for extended warranty. Eclipse is not sold on the net, if you do find it, and you will, be well aware that there is NO WARRANTY from Eclipse, NO THEFT REPLACEMENT, and no support. Thus point 10, buy from a specialty retailer. Hope this starts you on the right path.
Top Secret, I can tell you but then my wife will kill me.