Any DVD I make, I like to make a Master Copy for myself and I always put a diskskin on it to help prevent scratching on the disk. I also like to include the art work on the Master Disk (Data/DVD Combo Disk) or on a seperite CD stored with the Master DVD. When ever more copys are needed I just make a copy of the Disk, No need to keep it all on the computer. If it was a disk that I needed copys on a reguler bassis an additonal Disk Image kept on the computer if a good Idea.
As far as hard drive space, hard drives are relitivly cheep these days so I would probably just get an additional Hard Drive