Difficult question because no answer is completly correct in all cases.   For Video Editing data drive the fastest drive would be RAID 0.   But this leaves you No protection, when one drive fails you loose all data on the RAID 0 volume.   But if you backup offen this may not be an issue.  

For the System drive, I would go with RAID 1.   In the event you have a crash on one of the system disk, you can continue to run, replace the drive and re-build the array.  Speed may not be as fast as RAID 0, but you have the protection.

Thanks for the info.

So I understand this, I cannot have my primary HDD as a system, for programs, OS, etc, and also have a secondary, just to store video?

It'll be video stored on both HDD, if I go with a Raid 0?

Also, are there any brand names of HDD you can recommend that will be compatible with my XPS 600?

Thanks again!

So I understand this, I cannot have my primary HDD as a system, for programs, OS, etc, and also have a secondary, just to store video?
No you can add a second HD and not have it part of a RAID.  On my XPS gen2 system I have 4 HD two setup as RAID 1 volume and two non RAID disk.

It'll be video stored on both HDD, if I go with a Raid 0?
With RAID 0, data is stripped between two or more drives (Dell only support RAID 0 with 2 drives), stripping leads to a better performance since data can be written to two disk at the same time or read.  The draw back is a bigger chance of loosing all your data, if one of the disk fails all data is lost on the RAID 0 volume.

Also, are there any brand names of HDD you can recommend that will be compatible with my XPS 600?
If you buying a drive to setup RAID 0 or 1, you should purchase a drive of the same make and model as the drive you are going to migrate to RAID 1 or 0.  
Otherwise Segate, Western Digital are both good.   Maxtor seems to have a lot of failures recently so I would stay away from purchasing Maxtor.  Also remember your disk interface is SATA 1 or 2.   Not IDE.

If you buy a SATA Drive kit it will come with everything you need.   Including cable.    If you by a OEM drive usually cheaper the cable will need to be bought separtly.   Sometimes the kits may have a better waranty than just buying the bare drive.   Depends.

Rember you want to buy a SATA-1 or SATA-2 drive.  

Open the case, remove the drive.   The make and model shoud clearly be visiable.

Using the hardware profile may work but the method above will work for sure.

I use dual 160 gig sata hdd ins a raid 0 array, for my os and software, and 2 160 gig ide drives in a raid 0 array (1 installed in the floppy bay, one mounted behind the media card reader bay), running off an add in pci raid ide card bought a tiger direct for 19 bucks for my working video files, works great for all my video ripping, and burning needs.

Dave S