Please Critic High Mid Build

First off I would like to say THX for the great advice that you all give on these forums (Shadowduck, AEVM, .....)

I am still on the fence of what i want to do on my "high end" build, so I decided to wait a bit for the new ATI 4780x2 to come out and the new Lian Li PC-X2000 case.

While I procrastinate IoI, I need to put together a new computer for my kid. I thought it would also be a good learning experience before I attempt my higher end build. Having done a good amount of reading here, this is what I put together:

Intel Core 2 Duo E8400 Wolfdale 3.0GHz LGA 775 65W Dual-Core Processor Model BX80570E8400 - Retail
Model #:BX80570E8400
Item #:N82E16819115037
http://www.newegg.com/Product/Prod [...] 6819115037

-I think Qaud Core would be overkill for my kid's needs.

ASUS P5E Deluxe LGA 775 Intel X48 ATX Intel Motherboard - Retail
Model #5E Deluxe
Item #:N82E16813131317
http://www.newegg.com/Product/Prod [...] 6813131317

-want to keep open to Crossfire in the future
-As an alternative........
GIGABYTE GA-X48-DS4 LGA 775 Intel X48 ATX Intel Motherboard
The Gigabyte board is, however, out of stock on Newegg

SAPPHIRE 100243L Radeon HD 4870 512MB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail
Model #:100243L
Item #:N82E16814102748
http://www.newegg.com/Product/Prod [...] 6814102748

-I know I could spend less for a 4850, the extra $ not a big deal
-Also is an nice combo deal with the PSU

ARCTIC COOLING MX-2 Thermal Compound - Retail
Model #:MX-2R
Item #:N82E16835186020
http://www.newegg.com/Product/Prod [...] 6835186020

LITE-ON 20X DVD±R DVD Burner With 12X DVD-RAM Write Black SATA Model LH-20A1S - Retail
Model #:LH-20A1S
Item #:N82E16827106057
http://www.newegg.com/Product/Prod [...] 6827106057

XIGMATEK HDT-S1283 120mm Rifle CPU Cooler - Retail
Model #:HDT-S1283
Item #:N82E16835233003
http://www.newegg.com/Product/Prod [...] 6835233003

XIGMATEK ACK-I7751 Retention Bracket - Retail
Model #:ACK-I7751
Item #:N82E16835233019
http://www.newegg.com/Product/Prod [...] 6835233019

Thermaltake W0116RU 750W Complies with ATX 12V 2.2 & EPS 12V version Power Supply - Retail
http://www.newegg.com/Product/Prod [...] 6817153038

-might at some point Crossfire this set up. I also want a modular set up. I read somewhere that a single 12V rail is better, which this PSU does not have.
Corsair PSU seem to be very well regarded here. Their 750W version is not, however, modular. Any recs here for a better modular PSU would be appreciated.

Creative Sound Blaster X-Fi XtremeGamer 7.1 Channels PCI Interface Sound Card - Retail
Model #:70SB073A00000
Item #:N82E16829102006
http://www.newegg.com/Product/Prod [...] 6829102006

G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model F2-6400CL4D-4GBPK - Retail
Model #:F2-6400CL4D-4GBPK
Item #:N82E16820231148
http://www.newegg.com/Product/Prod [...] 6820231148

-Any good Corsair or Mushkin altenatives?
-1033 is not needed unless I there is intent to aggressively overclock?

Seagate Barracuda 7200.11 ST3500320AS 500GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
Model #:ST3500320AS
Item #:N82E16822148288
http://www.newegg.com/Product/Prod [...] 6822148288

Microsoft Windows Vista Home Premium SP1 64-bit English for System Builders 1pk DSP OEI DVD - OEM
Model #:66I-01939
Item #:N82E16832116488
http://www.newegg.com/Product/Prod [...] 6832116488

COOLER MASTER cosmos S RC-1100-KKN1-GP Black Aluminum ATX Full Tower Computer Case - Retail
Model #:RC-1100-KKN1-GP
Item #:N82E16811119150
http://www.newegg.com/Product/Prod [...] 6811119150

=$1,500 on Newegg, $1,400 ish with included rebates.

THX!

Single rail +12V vs multi-rail +12V PSUs isnt as important an issue as buying a high quality PSU.
Even with aggressive OC'ing DDR2 800 RAM should be fine with the FSB:RAM ratio's available to the ASUS P5E Deluxe. They allow you to run the RAM at 400Mhz (for example) while the CPU will run at another speed.

Alright, here's my two cents:

As far as the processor goes, I'd recommend stepping up to the E8500. It's only a little bit more and if you ever want to OC it: more headroom.

For the PSU, I'd strongly suggest getting a single-rail power supply. I'm going to be purchasing this one soon as it has outstanding benchmark results and reviews and has been touted as one of the most stable PSUs on the market:
http://www.newegg.com/Product/Prod [...] 6817139006

Lastly, I'd recommend going DDR2 1066. There's an improvement over DDR2 800 and you're guaranteed that the memory will run at the speed it's said to (as long as you buy quality RAM and a mobo with 1066 standard). You asked about Corsair and Mushkin and I'd recommend these as DDR2 1066:

Corsair Dominator 4GB (2 x 2GB) DDR2 1066:
http://www.newegg.com/Product/Prod [...] 6820145197

Mushkin equivalent:
http://www.newegg.com/Product/Prod [...] 6820146785

If you decide to go a step higher on the RAM, make sure the specs are set right in the BIOS.

I'd personally go with the Corsair. They're both about the same as far as specs go.