Agree o1die,
Cpu for video editing:
core i7 920 (LGA 1336, X58)
or
core i7 860 (LGA 1156, P55)
will be the best. The 8 threads the i7 offers will be put to good use.
Do you have a microcenter or Frys near you aennabe?
X58 platform:
Core i7 920:
Microcenter $229.99
http://www.microcenter.com/single_product_results.phtml...
Newegg: $288.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
OCZ Gold 6GB (3 x 2GB) DDR3 1600 $149.99 ($129.99 after $20.00 Mail-In Rebate)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
ASRock X58 Extreme $169.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Antec Three Hundred $59.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
XFX HD-575X-ZNFC Radeon HD 5750 1GB 128-bit GDDR5 $139.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Antec EarthWatts EA650 650W $74.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Western Digital Caviar Black 2TB 7200 RPM 64MB Cache SATA 3.0Gb/s $299.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
P55 platform:
Core i7 860:
Microcenter $229.99
http://www.microcenter.com/single_product_results.phtml...
Newegg: 279.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
OCZ Gold Edition DDR3 1066MHZ 4GB (2 x 2GB) $79.99 (there faster ram but this is fairly cheap and you wouldn't notice the performance difference between 1066Mhz and 1333MHz ram)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
GIGABYTE GA-P55M-UD4 LGA 1156 Intel P55 Micro ATX $139.99 (can go cheaper if sli/crossfire not needed in future)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Antec Three Hundred $59.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
XFX HD-575X-ZNFC Radeon HD 5750 1GB 128-bit GDDR5 $139.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Antec EarthWatts EA650 650W $74.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Western Digital Caviar Black 2TB 7200 RPM 64MB Cache SATA 3.0Gb/s $299.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Total cost of hardware: (if getting all from newegg with rebates and saving)
X58: $1163.93
P55: $1074.93
For an OS: Add another $183.49 for windows 7
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
X58: $1347.42
P55: $1258.42
Sorry with it coming slightly over budget when including an OS.
Although if you can fit this budget, it will be a great video editing system.
Hope this helps. (if anyone else can edit this to make it fit the budget better, feel free to do so.)