I've had a mix of audio, I've had 2 Kenwood, 1 Pioneer , and 2 Sony Headunits. The best one by far was the Pioneet, although it wasn't MP3, and thats what I really wanted, so I bought a sony one.
Amps: I've had a few of these as well. Had Boss (crap) SPLX (really good vaule for money) and have now got JBL, which I love. Got this one:
JBL P180.2
Subs: Had Kenwood 10"(fired the voice coil), Magnat 10" (sold as it was in the wrong box), had a boss 2x10" in a bandpass box, was really good for deep bass, but no good for Dance music. Now I'm running a JBL GT4 15" in a sealed box. Kicks nice and hard, and can drop really low when needed.