You're gonna need a shelf if you want to collect all the different versions of the trilogy.

I have:

Dr. Gonzo's DE LD transfer 4 discs
Moth3r's PAL set 3 discs
Dr. M's Reinventing the Wheel set 3 discs
Editdroid's transfer 3 discs
OCP's Classic Editions 3 discs plus 1 for version 2.0 of ANH
Darth Editious SE ANH version 1.0 and 3.0
Wookie Groomer's split screen set 3 discs
Deleted Magic
Building Empire
Returning to Jedi PAL dual layer and SL and NTSC SL

and if you include the official releases, you're looking at about 30 discs. And if you include the rare stuff by Baby Hum, your talking about a 50 disc set.