First time building, wish to use for personal use/gaming, possibly multimedia (blu-ray?)
Case: CM 690
Power supply: 650W
Motherboard:
CPU: Intel Core 2 Duo E8400 OR E8500
RAM: 4G
Graphics Card: ASUS Radeon HD 4870 (EAH4870)
HDD: WD320/500
Optical Drive:
OS: XP, Linux

Need help with
What brands to look for in power supply and what Motherboard (preferably by ASUS)

Thanks!

This is a good PSU. I have one myself. And it has a reasonable price.

the Gigabyte GA EP45T-UD3LR is a good mobo and it uses DDR3 memory.
dont waste extra cash on the E8500, go for the E8400 and even a slight overclock will outperform the E8500, the E8400 can overclock to 4.0ghz on a stock cooler, but i dont recommend that, if you want to overclock get a aftermarket cooler.
650W PSU seems a bit excessive, you can get away with 500W
ive put together a list for you, cause i cant sleep, you said ATI 4870 so i worked on that, id prefer nvidia but thats just me, here you go.
build:
CPU Intel Core 2 Duo E8400 3.0ghz $168 here
Mobo Gigabyte GA EP45T-UD3LR $85 (after rebate) here
or
ASUS alternative P5E3-pro $135 here
this mobo supports DDR3 and Crossfire (2 x ATI graphic cards for extra power)
RAM Crucial ballistix 4GB DDR3 1333 $69 here
WD caviar blue 500GB HD SATA 16mb cache $70 here
Saphire radeon HD4870 1GB 256bit $164 here
Antec 500W 80plus certified $70 here
or go for the one WHS mentioned its only $9 extra and for 650W it seems reasonable
Sony Black DVD-RW $30 here

Total so far is a measly $656 (gigabyte mobo) or $705 (ASUS mobo) still plenty of room for a decent case (antec 900 comes to mind only $90)
OS is your choice, and i dont know anything about monitors.
hope this helps

agreed, if you serious about gaming then go for a quad CPU, although the E8400 has proven to be pretty good with high end games, a quad CPU is also better for future games and multi-tasking applications.
id suggest the Core 2 Quad Q9400 2.66ghz for $190 here
same specs as E8400 but with 2 extra cores. easy overclocker aswell.

It is true that only certain apps can fully benefit quad-core.
And If you can imagine DDR1, DDR2 and DDR3, as roads. Cars (automobiles), for a set amount of traffic, they will pass faster down a 3 lane road, than a 2, or a 1 lane.

To add to what LH wrote, as far as power consumption goes, DDR1 is a supercar, DDR2 a V8 and DDR3 an economically friendly Mini. :)

where exactly are you? can you not order from newegg? if your in Canada then try tigerdirect.
if you cant get the ASUS mobo in your country then go for the Gigabyte one i suggested, its also very good, just doesnt have the luxury of 2 x graphics cards. let me know what country you are in i might be able to help you if your in an asian country as im in China

heres a few sites to go to in Asia........ i use them for parts.

www.newegg.com.cn

www.pchom.com (taiwanese website i belive)

www.taobao.com

sould be good prices on there, i found the antec 900 for about 700 chinese yuan, which is like $100 (american)
hope it helps

look s good, remember with the different Motherboards some use DDR3 and some DDR2, just be sure once you have got the motherboard before you buy the RAM.
i looked at the CM690 its actually a nice case.good airflow.
OS advice, im a huge XP fan but for gaming its best to use Vista SP2 mainly because of the Directx 10.1 that Vista uses, Xp can only use DX 9c.
and when using the HD4870 you will want to use DX10.1 to make the games look much better!!

well its a good idea, win7 seems good, havent tried it myeslf, i know it uses the new Dx11, most of Dx11 is compatible with DX10.
before getting Win7 make sure the motherboard you decide to buy has the latest drivers available for Win7.