Help Me Build A System

i need some help deciding on parts for my sound system. i have an alpine deck with 2 12 inch infinity subz. this past weekend in took it out of my old car and was gonna put them in my new one. but then i thought about adding new speakers inside the car and if i should amp those. first off, what kind of speakers are good. i was looking at infinity or alpine. there aren't a lot of car specialty shops where i live so i'm limited to name brand type stuff. if i get some new speaks then i would like to amp them. i talked to one guy and he said to think about getting a 5 channel amp, to power everything
i was thinking more like two amps, one for my subz and one for my speakers. i would then need a cap as well. if anyone has any, ANY, help in any area here please help me out.

Using one amp for subs and another for speakers is a smart idea. I would recommend a 1-channel or "mono" amp that is class D for your subs and then a 4-channel amp for your speakers.

infinitys are nice speakers for vocals and guitars, polks are a good choice if you like deep bass

I prefer MB Quart for interior speakers. I have JL components and am satisfied with them. I second the four channel amp.

where can i look at MB Quart speakers?
also would you all suggest i go with a speaker that has better vocal because i'll be getting plenty of bass through the woofers.

Mb Quart is what you are looking for then. Here is there site http://www.mbquart.com . I have found them alot cheaper on ebay. Im guessing you have 6.5" . Here is a set that i have found http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=32819&item=5711325059&rd=1 . These are inexpensive and sound good. I had a set last year in my old car.