My new system - advice please

This is what I got at the moment, some parts are from my old system.
I am seeking opinions and advice.

CASE: THERMALTAKE SOPRANO BLACK
CASE FANS: 2X 12cm standard fans (front+back) + 1x 9cm standard fan (side) (SHOULD I CHANGE IT???)
MOTHERBOARD: ASUS P6T DELUXE V2
CPU: intel i7 920 d0 (2.66)]
CPU COOLER: STANDARD INTEL CPU COOLER (WILL BE CHANGED)
MEMORY: OCZ Reaper6Gb DDR3 1866MHz (3x2Gb) Tri-Chanel
PSU: SEASONIC M12D - 850W
FAN CONTROLLER: ZALMAN ZF-MFC2
GRAPHIC CARD: NVIDIA GEFORCE 8600GT 512MB (WILL BE CHANGED)
SOUND CARD:CREATIVE AUDIGY 2ZS
ONBOARD AUDIO: ADI AD2000B 8 -Channel High Definition
SPEAKERS: CREATIVE INSPIRE T7900 7.1
HDD1: WESTERN DIGITAL WD6400AAKS 640GB
HDD2: WESTERN DIGITAL WD2500JD 250GB (WILL BE CHANGED)
DVDRW: PIONEER DVR-216
monitor: (using lcd tv - sharp aquos 37" 1920x1080) new monitor will be purchased later

Question1:
Should I change case fans???

Question2:
cpu cooler: thinking to get - Prolima Megahalems Super 6 Heatpipe Tower Cooler + choice of cpu fan?
http://www.scan.co.uk/Product.aspx [...] ID=1040994
test:
http://benchmarkreviews.com/index. [...] mitstart=7

question3:
graphic card: I'm thinking about - Zotac 896Mb nVidia GeForce GTX 275 AMP
http://www.scan.co.uk/Products/896 [...] x-DL-DVI-I
tests:
http://www.videocardbenchmark.net/high_end_gpus.html

question4:
hdd2: WESTERN DIGITAL WD6400AAKS 640GB - connected raid0 for better speed?

Thanks for your opinion.

This computer is for gaming I'm guessing.

just fill out the sticky from theanimal's thread at the top of home built systems and it will help us help you out.