Are you asking about physical disc storage? I usually just store them on my bookshelf once I've ripped and converted to m4v's and load them into iTunes so I can stream them to my AppleTV2.
Finally cracked after walls with floor to ceiling shelving I am ripping them all, extras, soundtracks the lot.
As I rip them, I scan the DVD dust jacket, add the disk to a pile of ripped disks, when I get to about 100 wrap them up in cling wrap and drop in the boxes with 1,000 s of the DVDs ripped so far.
They are my third level backup.... it is a Long long rip