general feeling around here is 'just take your pick...they all sound the same for that price'. it's difficult to get the WHOLE PACKAGE for $100, if it were that easy i would have saved about $4500.
If you are going to have a subwoofer/satellite system with separate amps, a component system would be the way to go... you can get madisound components at madisound.com for as low as $120.00
If you are just going to stick with head unit power and 6X9's, look at Pioneer Rev, PPI, and Crystal mobile sound Kevlar (yellow cones)