video editing system - I need advice

[marceggers]

I recently received a Dell Gift Card as the result of a promotional sales drive at work. It's for $2000. I want to use it to buy a system that I will use solely for desktop video editing, particularly putting VHS onto DVD.
The more I read and research the more questions I have. So let me ask a few and give me all the feedback you can.

To start with, the processor: I think I've gotten the impression that dual core processors are great if you plan to multi-task a lot. I don't think I'll be doing much of that so should I get the fastest single core processor I can afford?

Next, I know I need a lot of RAM, like 2 gigs, but Dell sells both 533MHz and 667 MHz dual channel RAM. Do I need the faster and more expensive (667 MHz) or will the 533 be sufficient?
Third, I want a good video card with at least 256 MB video memory but Dell offers two different ones: 1)- 256MB PCI Express™ x16 (DVI/VGA/TV-out) nVidia GeForce 6800, and 2)-256MB Nvidia GeForce 7800 GTX at $400 extra! Do I need it?
And finally, about my harddrives (plural), should I spring for RAID or will the serial ATA variety be good enough.
I know I'm asking a lot, but I don't want to make bad choices or spend much beyond my $2000 freebie. Thanks for whatever you can share.

[sneaks59]

How much hard drive data are we talking can you afford to loose your data?
I would want to, I understand Raid very well and consider it to be an advantage over none raid if your not one to back up. Then I would say yes to raid but what controller to choose from? there a new PCI-Express Controller out from Promise Technology called A SuperTrakEX8350 has 8 ports and does Raid 6. What is Raid 6 double the Parity. so you could feasbly loose 2 disk and still maintain your data integrity. The price is a bit high but I could have 8 500GB drives and with two disk for parity and still have 3TB of Space. I like that even for a server or file system enviorment wow! anyhow its a thought!