Seabass

Hey everyone, ok this is what im going to be hooking up, i need a little help explaining how i should do all of it. Ok there will be my cd player(panasonic with aux out...ect) My jbl bp1200.1 amp, 2 15" fosgate hx2's, a 900mhz hp computer(someone gave it to me for $50), a lilliput vga screen, 2 audiovox flipdown 7" screens, and 1 xbox with a matrix modchip and 120gig hd. Ok so this is how im planning to hook it up. Cd Player-> subwoofer out-amp->Subs.
Then Aux Out left and right out to the front speaker input on the sound card of the computer. Then the computer is hooked up to the vga screen and the vga screen is also hooked up to the xbox. Then the rca screens are only hooked up to the rca screens. Sound good? I heard some people talking about hooking up their computer straight into the amp, why would you want to do this? Also how many watt inverter do you think i should get? And 1 last thing, what sound card is good for carputers...i have a 5.1 live i can get from my other computer, sound good? Thanks everyone.