Originally posted by: Hulk
Don't worry about the video card, it will have no effect on video editing performance other than if it is dual head you can send one feed to a preview monitor, which is really nice if your software supports it.
Ideally I'd go 20" for main display and 17" for preview monitor using dual head. I would do normal aspect ratio (not wide) on the 20" so you can see more stacked tracks, the height is more important than the width of the display for video editing in my opinion.
RAID is unneccessary. Standard definition and even HDV will be cpu bound long before it will be disk bound. That is unless they will be editing uncompressed HD video or an instane number of feeds, like 8 or more. I doubt the kids will be editing more than 4 or 5 streams (cameras) at once so you'll be fine with any modern 7200rpm SATA drive. Most likely they have a camera feed or two they'll be cutting up. I personally wouldn't spend to much time teaching them the software but instead teach them how to edit footage into an interesting story. Once rolling they'll figure out the software themselves.
2GB of memory will be no faster than 1GB for XP if they are ONLY video editing. I can't speak to Vista as I have not tested it. Save the memory money and put it into a faster cpu. You can always upgrade the memory later if Vista requires it.
Buy the fastest CPU you can as that will determine performance more than anything else.
I've written a few books on DVD authoring and have spoken at NAB about video editing so I do have some experience on this matter.
+1 with a caveat
1GB multiple drives over 2GB single.
Disagree a little on video cards (my caveat) - The latest Vegas and all Avid products are tied to video performance (well Xpress and is larger siblings are tied more to a card line). After Effects latest version is also now using the GPU too from the specs I remember. But, the 7300 should be fine for PP in DV. In this situation, Hulk is on target that it will not get you much more. nVidia is a better choice with Adobe and Sony than ATI (if you were using Avid Liquid or Pinnacle Studio - you would want ATI over nVidia.)
I have RAID 0 volumes as I will multicam and have multiple feeds including HD. It is a myth that R0 is half as reliable. The real statistics involve MTBF, standard deviations, and may be eclipsed by other components in the system. It could be that you would decrease MTBF from 10 to 7 years, but that is a mean/average which is just another 'statistic'.
BUT, if you can get away with using three individual drives, do it. It will speed up your bootup and load to go with a Raptor, but the extra cost could have bought a 500GB and any slack on the OS drive can be additional "offline" storage for completed ISO files or project backups (I think PP2 supports backup). I have 4 250GB drives, a 400 R0, and a set of Raptors for OS. The Raptors do nothing for my performance while editing. My 400 volume can get me about 4 lines of HD in combo with my processors and my X800XT and the 250 (Rendered is on it - the more I render the slower the playback as the 250 becomes the bottleneck along with the AGP bus if I do not render the streams). That is HD 1080 in Liquid, which operates completely differently than PP. But still get the extra drives.
edit - Based on update OP, still try nVidia. Would like to see 1x250, 1 x 400, 1 x 250+ if it were me.