Here's a modest list, under budget, and will satisfy you. I guarantee you. It's a mix of stuff I find to work well.

H.U. (Select all add-on installation options. Everything you need will be included. No need to go to Crutchfield and pay much more.) Kenwood DDX318 + KNA-G610 Navigation 6.1" LCD DVD/CD/MP3 Player

Components for front (Includes sound dampening so it won't sound hollow): Focal 165A1 + NVX SDSK2 5-1/4" Car Speakers w/ Sound Dampening

Coaxils for back: You just choose a coaxil that'll match up to the 4-channel amp's rms.

4-channel amp for compoents/coaxils (Dont' worry about the seemingly low rms. Very efficient and too much is pointless for a good mix.): Image Dynamics i4500 4-Channel Class AB i Series Car Amplifier

Box: link provided above.

Subs (2): Kicker 10CVT102 (10CVT10-2) 10" Shallow-Mount Comp VT Subwoofer

Mono for subs: Image Dynamics Q600.1 (Q6001) Monoblock Class A/B Q Car Amplifier OR RE Audio DTS-1500.1 (DTS1500.1) 2000W Monoblock Class D Amplifier OR Rockford Fosgate R750-1D (R7501D) 750W Monoblock Class D Car Amplifier

Don't buy Wal-Mart wiring. I don't care how many peoples' stuff sounds "good" on it and works fine. Get 4 gauge for the mono, and 8 gauge for the 4-channel. Better yet, here:

Mono: Kicker ZCK4 (09ZCK4) Complete 4 Gauge Z-Series Amplifier Kit

4-channel: Kicker ZCK84 (09ZCK84) Complete 8 Gauge Z-Series Amplifier Kit

Get it all dialed in, and you're good.