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?WebProductID=1040994
test:
http://benchmarkreviews.com/index.php?option=com_conten...

question3:
graphic card: I'm thinking about - Zotac 896Mb nVidia GeForce GTX 275 AMP
http://www.scan.co.uk/Products/896MB-XFX-GTX-275-XXX-PC...(x16)-2268-MHz-GDDR3-GPU-670-MHz-240-Cores-2x-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.