Epic Build Or Epic Fail?

First of all I will not be following the suggested guidelines for new build requests for the simple reason that what I plan on building just can't fit properly in there.

Goal : Upgrade my current Core 2 Duo setup to last me a while before Sandy Bridge makes a decent comeback.

The Plan :

1) Insert my old skool Asus P5LD2 Motherboard (http://usa.asus.com/product.aspx?P_ID=gD1ljCkUWy1Y3yMG) into my new HAF X Case.
2) Order the following items.

- Intel Pentium E6700 Wolfdale 3.2GHz LGA 775 65W Dual-Core Desktop Processor BX80571E6700
http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...

- G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 667 (PC2 5300) Dual Channel Kit Desktop Memory Model F2-5300CL4D-4GBPQ
http://www.newegg.ca/Product/Product.aspx?Item=N82E1682...

- XFX Core Edition PRO850W (P1-850S-CAB9) 850W ATX12V v2.2 & ESP12V v2.91 SLI Certified CrossFire Ready 80 PLUS BRONZE Certified Active PFC Power Supply
http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...

- EVGA 012-P3-1570-AR GeForce GTX 570 (Fermi) 1280MB 320-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...

3) Slam these things into my little P5LD2 motherboard with windows 7 running on top of it all

4) Overclock if possible.

Now I will technically only be "wasting" 200$ on the processor and memory, the rest will all go into my new build in the future. Now I need to know how badly of an idea is this? Right now my mind is very pleased with itself for coming up with this so its hard to detect flaws. I figure I do this instead of go all out and buy a LGA1366 which would cost way more than 200$ and wont even be the latest technology. I am also very concerned with compatibility issues between the beasts and the school girl motherboard.

Any advice would be appreciated!