okay, a few months ago i bought a new head unit.. it's the sony one with the black ghost face that unfolds and everything. it cranks out 50 watts.

now.. i want to eventually have a great system, but piece by piece. what am i supposta get next? i just want a great sound quality.

so is it a sub? an amp? or speakers? i have no idea! i talked to the guy at the audio place and he said that if i get a sub i have to get an amp. is that true?

thanks for any help!