I use 64k stripes, but next format i'm moving to 128 (or larger, going for biggest)
all I use RAID for these days is storing my videos, (had 136GB this morning, but by the time i get home, i betting on 140

)
I have a 200GB that holds my OS, page file, APPs, and MP3's
all my Doc's and Pic's are on a network drive
I've heard that promise reccomends keeping your os on IDE and just your page file on RAID. that should help performance a bit. Considering what i use it for (transfering of large files) i dont ever see myself moving the page file.
I've got RAID on 2 PC's now, that are connected using a Gigabit direct connect for lightning fast file transfers. can drop 2 hour movies in <30 secs
