Help me build a PC... with a twist!

Warning: This twist is probably going to be pretty lame.

So I need to build a fast, but reasonably-priced PC for work (~$1500 or less, no monitor). Instead of being a blazing gaming box, however, I need something that lets me edit video with the power of ten thousand suns.

Now we’re not doing HD work or anything—most of this stuff will end up online at YouTube-like quality—but that’s no reason not to get the best machine I can while the getting’s good.

Here is my initial thought:

Athlon 64 X2 4400+ (This is the step up for the bigger cache, ne?)
10k RPM Western Digital Drive (or Drives) as video scratch drive.
Some other giant drive (or drives) for longer-term video storage.
Some motherboard.
A hunka RAM. (2GB or more.)
Some videocard, preferably one that supports video acceleration (which seems like most of the modern ATI and Nvidia stuff.)
Sundries (Case, keyboard, etc.)

My main questions are: Does anyone know if SSE2 performance on Athlons is in the same league as the Pentiums? Is more RAM than 2GB going to make a difference? Can I possibly do dual-processor on my budget, or is it better just to get a fast dual-core? And anyone have a good motherboard suggestion that includes FireWire? (I tend to just go with Asus when I’m too busy to do the research.)

Thanks for any help you’d like to offer, esp. if you’ve had some experience building video editing boxes before.

Your main bottleneck in an editing station is disk speed. For disk subsystems, I would get:

1 250GB drive for the OS, MS office, whatever. A 7k250 would work here.
2 146GB WD 10k raptors in a raid0 stripe for video scratch space. If you’re editing low-res low-duration content, you could drop back to 2 73GB raptors.
2 500GB hitachi deskstar 7k500’s in a raid1 mirror for longterm secure video storage

The rest really doesn’t matter all that much. The CPU only really comes into its own when you’re encoding video for end use, not editing it together. If you will be responsible for encoding as well as editing, intel CPUs tend to be somewhat faster. You do want to get 2GB of RAM.

What stuss just said.

Get two of the fastest PC hard drives and place them in a striped RAID for your works in progress.

After you are done editing for the day, copy your work-in-progress to a large, mirrored RAID partition.

Nothing else matters.