This is just an opinion, but for speakers and amps I would say-
Amps-
Kenwood amps have excellent performance for the money, the KAC-9152 puts out 900 watts rms into 2 or 1 ohms for around $350.
Subs-
Pioneer's SPL series subs Have great SQ and SPL for a good price.
Infinity-
Good SQ subs and excellent coaxes and components.