Hey rev...
To be honest, the amount you want to spend will not get you very much.
Your biggest single expenditure will be your amp; For the amount of money you want to spend, I'd say pick up a 5 channel.
I'll just throw some links and prices at ya:
Here's a good amp, it isn't the BEST amp, but it's good quality and a fair price. I'm running an older amp made by Autotek in my truck and it's a great value for dollar amp. 4x55w RMS / 1x220w RMS. The four smaller wattage channels are for your door and rear speakers. The larger one is your sub channel.
http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=18182
6.5" 2-way's. You could get 1-ways for cheaper, but the range of sound isn't nearly as good.
http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=11401
10" sub... You really only need one. Trust me on this...
http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=12512
SO... here we're looking at:
Amp:$359
2-way's:$218 ($119x2)
Sub:$149
Total: $726 (no head unit)
Run the 6.5"s off the head unit and you can get an amp for $169 ($536 total):
http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=18149
I'd steer clear of sony; their stuff is cheap, and over priced for what you get. Also, I'd think long and hard about how much you want to spend... What I just showed you are basically base line products; go much lower than that and it's almost not even worth the money. Keep in mind that you get what you pay for; a $50 pair of 6.5"s won't sound as good, and won't last as long (speakers do wear out). Also, speakers like power; they run cleaner and more efficiently when they are running on wattage within their range, this is why most that go with full aftermarket stereos run everything on an amp). And last but not least... If you can save up the money... throw in an in-dash double din flat panel!!! It will look so much better! Kenwood, pioneer and alpine all make em for between $450-$700ish.