Build video editing computer and spend somewhere around 15 to 20% of your budget on the best video card you can afford. If you're not sure how to do that, follow the link above and I'll help you pick the best one for your build. Look for a card that has at least 1GB of onboard memory. Ideally what you will be looking for here is a fast card that benchmarks well, read the options and make sure the card has all the options you want as well.
Get yourself a motherboard that supports raid striping, then get multiple hard drives and setup a raid. This will cut the file transfers down by at least half and be a huge performance boost. Build video editing computer using a SATA Raid, you really won't regret this. I've become so addicted to the speed boost or reading and writing files I get from this, after my first raid build, every computer I've built for myself or my wife has one.
With the power of the newer CPU's and the speed of the RAM out there, you really need to look at this option. It's not far fetched to have a computer fast enough that it can edit a video faster than the hard drive can handle the read and writes. All the CPU in the world won't help you can't provide it with information fast enough. My current 4 core AMD x940 does this at times with a raid.
Follow all the tips on this page, you will make the best video editing computer that money can buy, although similar to a gaming computer, some options still need to be changed to make it a better fit for video work, rather than rendering games.
Since almost all of the software you will use when editing video is multi-threaded, that is software that can use the full benefit from CPU's with multiple cores, CPU choice is also an option to revisit. You'll use the same method picking the best CPU as you normally do, but, if you have 2 CPU's that come close on score and review, you'll check to see which one has more cores.
At the time of this writing I'm referring to Intel i920 or the
new AMD
6 core.
Although the i920 will probably score better on a bench, the 6 core AMD
will probably be the better option as it has 6 cores, not 4 when it
comes to using good software that knows how to use your hardware.
Plus, you'll most likely spend less money on the faster
performing 6 core AMD, as far as video editing is concerned.
There is no question, Windows 7 64 bit is the place to be for this computer. You need the ability to multi task and handle workload on the cores of your CPU. It also handles the use of RAM really well adding additional speed benefits to all of the hardware we have picked out.