One thing that I didn't see touched upon is since you have a variety of taste (I do too, listen to house music, rap, metal classic rock) then you will not want to go with anything bigger than a 12" sub(s) in the future. Anything bigger than 12" will sound muddy. I don't care how much power you have to it, it's simply to big and pushes air to slowly and too much of it to get a "tight" hard hitting bass response (like a kickdrum of a drummer) to sound good. 15's and the like are suited for rap and other musci like that. Believe me if you want to sound like you are at a concert get 12's and 1- 12 sub will be sufficient. Get a high powered sub and get an amp that is about 10% higer in wattage output than that and that will drive that sub that way it's supposed to be driven and produce great sound. Make sure the enclosure is sealed. 3-4 GENERAL numbers to look at when getting a quality sub(s)
QTS - between .30 to .90. These speakers offer good control, low Distortion and high power handling
Qtc of .7 has smoothest response and the lowest resonant frequency response. A Qtc of above 1.1 should only be used by those who prefer a "boomy" response.
RMS - continuous wattage it can handle. Don't look at Peak wattage, this is the maximum wattage it will give you on a surge or just before it fails.
Db - sensitivity....basically how loud it produces sound and how efficiently
I have one sub in the back of my cherokee and I built it using a sealed box with 1.15 cu ft enclosure volume. Here is the sub I used.
http://www.mainstreet-audio.com/Mer...=PROD&Product_Code=29025&Category_Code=ADSSUB
It is an awesome sub driven by a ppi amp 500Watt amp here:
http://www.mainstreet-audio.com/Mer...n=PROD&Product_Code=48300&Category_Code=PPAMP
The sound from the one 12" sub is amazing, it hit hard, where you can feel it in your chest in the front seat. Great combo with the sealed enclouse volume I built. It sounds LOUDER and cleaner than some other guys I kow with 2 subs running 1000 watts.
In general though great brands as mentioned in this thread that you can't go wrong with are JL audio, Rockford Fosgate and I still like Kickers (although I think they are suited for more hardcore bassheads). Also, mine A/D/S, are very good quality. They were always known for professional home audio and started making car audio as well.
Not ment to confuse you, figured you will need to look into this when ready to add a sub so was giving you a heads up.