Need help putting a new system together

I would ditch the extreme edition chip. You didn't say what your budget is, but since you chose an extreme edition chip, I guess it's probably pretty high. This would make an awesome rig:

Intel Core 2 Quad Q9550 Yorkfield 2.83GHz 12MB L2 Cache LGA 775 95W Quad-Core Processor - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $324.99

GIGABYTE GA-X48-DQ6 LGA 775 Intel X48 ATX Intel Motherboard - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $278.99

mushkin 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $76.99 -$20.00 MIR

POWERCOLOR AX4870 1GBD5-PPH Radeon HD 4870 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $299.00

SAMSUNG Black 22X DVD+R 22X DVD-R 16X DVD-ROM 2MB Cache SATA 22X DVD±R DVD Burner with LightScribe - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $25.99

Western Digital Caviar SE16 WD6400AAKS 640GB 7200 RPM 16MB Cache SATA 3.0Gb/s Hard Drive - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $79.99

CORSAIR CMPSU-750TX 750W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS Certified Active PFC Power Supply - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $129.99 -$20.00 MIR

Antec Three Hundred Black ATX Mid Tower Computer Case - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $54.99

You could try out the onboard sound and see if it's OK. A lot of the newer motherboards have pretty good onboard sound.

thank you for the effort in putting that together. and actually i didnt mean to pu the x there...i was actually thinking of the proc you mentioned. i am a musician and agervatingly picky about sound. So i guess i could try it out...but at the same time i am a little obsessed with max performance within a resonable price range. I look at a lot of reviews and charts. I am very heavly considering 4 hds in raid 0. I dont care about a failing disk. that is what dvds and jump drives(and the internet) are for...back up. I have a 4.1 klipsch set i still use and sounds great. its the older thx cert. set. got a couple of questions

in 4 years do you think a 4870 will be able to handle the games...even in crossfire. which you can always buy another one later when the games are actually made to work better with it. (knowing me i would rather spend more on 2 newer cards if i decided to wait....lol)

also, what is the difference between the extreme proc and the one you mentioned. same everything except clock speed which you will have if overclocked? is there a difference in mem controller?

also, will performance ram at tighter settinsg perform better then normal faster clocked ram?

A lot of what i do is peace of mind....i hate regreting and would rather buy what i want(knowing it is the best within my given price rang) now instead of buying ok now and spending it again later to upgrade.

oh, and what i'm also thinking is the q9550 and the x45 series chipset boards will be much much cheaper after the first ofthe year when they fade out those and start really pushing core i7 I want really good(i like have better then average), but i'm not loaded...lol i am a ebayer through and though...bargan hunter!

I was gonna build myself a new PC, but, I7 is so close now I am gonna wait for it.

well, since i will be using tax refund..i am forced to wait.lol..which may be to my good. Just depends on how fast core i7 will drop. it will be feb or maybe even march before it can happen....so we will see.

The extreme edition chips have unlocked multipliers so you can overclock using the multiplier and FSB instead of the FSB only.

DDR2 800 RAM at tight timings (around 4-4-4-12) and low voltage is recommended. The standard for DDR2 RAM is 1.8v. Any RAM at higher voltage is factory overclocked.

The X38/X48 chipsets will both run crossfire at full 16x speed. The p45 chipset can also do crossfire, but at 8x speed. This will probably actually have a noticeable difference on the 4870 1GB card.

The WD 6400AAKS HD is very fast. 4 in RAID0 would be sick and only cost $320. I don't know if many onboard RAID controllers will support a 4 disk RAID0 array. You'll have to research that.

the challenge of OC-ing a Q9450 to 3.6ghz is possible but beyond that is quite difficult. 4ghz is pretty much impossible for 24/7 operation. i've read many many many forums on the Q9450 as i have one myself, and i never read that a person has achieved a 4ghz 24/7 computer. one guy hit 4ghz running 500 fsb, it made it all the way through windows and enough for a screenshot, then he had to take it back down.

the Q9550 would hit a higher OC with the 8.5 multi, these chips have a fsb wall of around 450, so unless you wanna go over that limit somehow to reach the magical 4ghz, so good luck w/that, i wouldn't advise it, maybe a 3.4ghz OC with the Q9550.

and if you do want to achieve a great overclock, make sure all your other parts are top notch to handle the stress.