Bang for the Buck on a budget!?!?! Two companies come to mind...Pioneer and Kenwood. Premier or Excelon series will run you cheaper (most of the time) than any JBL/JL/Alpine equipment and still pound. Also try the Mach5 Audio subs cause Rudy and Mark both had those and they kicked the shit outta their cars.
Now if you can afford excellent quality stuff, I would highly recommend Audison amps and Focal components for the front as well as Focal Coax's for the rear. I have not seen (or heard) anything that can touch Focal for sound. I have Pioneer all around including my two 10" subs and they sound real good together. People with far more expensive systems have asked me what I am running because it sounds tighter than their systems. Good luck man and keep asking if you dont know. Andrew/Andrew/ and Rudy are all HUGE into car audio and may be able to help you as well.