i have found if you have a good sub in bad <good dosent mean big...it means clear and tight) and a good set of speakers up front buying rear speakers is a waist of money.
right now i have an pioneer head unit (forget the modle, but it was the mid grade flip down face, mp3 player, with remote) JBL GTO 6.5's in front. a JBL GTO 12 inch sub cone. i built the box to be a sealed 1cubic foot internal, filled with pillow stuffing and an alpine v12 amp pushing around 300rms or so and my system will blow your mind for only 3 speakers total.
get a set of component speakers up front and an amp just for those and damn youve got some kickin tunes.
