Alpine Alpine Alpine (Check Sig)...Alpine is the only company I know of that you can buy everything they sell and rock the crap out of people. Meaning, if you buy their head unit, amps, and speakers (including subs) you have one hell of a system.

Other good ones are Phoenix Gold, MB Quart, Boston Acoustic, Kicker makes some good subs, Rockford Fosgate.

Being a shop guy myself I know you can't carry all the top brand stuff or you'll go broke. So get some Kenwood and Pioneer in there too for your lower brands. But please don't get things like Rockwood, Jensen, Aiwa, or Profile.