JBOD isn't very useful, in my opinion. I would have chosen RAID 0 myself, if presented with the choice.
I have RAID 0 (160GB x 2, 32kb stripe size) and I can tell you there's not a lot of difference. Benchmarks tell me my RAID 0 increases sustained transfer performance by about 20%. But I'd be lying if I told you I noticed.
I've set up a file server with a couple of 500GB drives. So I'm probably getting rid of the RAID 0 because I don't need the space anymore. I might use the disks independently for a software backup or reconfigure to RAID 1 (which also provides a performance boost, just for reads)... Or perhaps implement both.
And would anyone recommend utilities that de-frag the drive(s) while the system is at idle
O&O Defrag = my favorite.
every time I say the word raid-0 around here I hear the same thing
I'm not sure RAID 0 means impending doom. There
is an increased risk of data loss because you have more variables to account for, but I don't feel like its much.
The idea is now you have to worry about two drives instead of one (doubles the potential of drive failure, which would affect the entire array) and controller/striping issues from firmware bugs, brown-outs etc... But as long as you keep things backup, there's not much to worry about.