I would always recommend the reiserfs. but if you are going to use it you have to use knx-hdinstall as knoppix-installer does not support reiserfs

reiserfs is a journaling file system it provides serious recovery and stability. I upgraded from ext2 to reiserfs maybe about 2 years now and I have never looked back

the only thing to be aware of is that using reiserfs with encryption does not fly with debian, its not recognized. I was using it with SuSE when I came to debian a few months now but it was a minor price to pay. Did a few reformat hard disk and installs until I figured out just to get rid of reiserfs encrypted hard disks.

xfs is also solid, also available with knx-hdinstall

so choose a journaling file system and enjoy