Storing DVD info for future use

I would like to be able to go back to some of the video clips later on and use them in a DVD. Right now, they are rather large files (35 gigs each). Of course after the transcoding in encore they are compressed to be much smaller.

I have an external 250gig firewire hardrive. Is it out of the question to just store the folder that is created in Encore when I made previous DVD's. In other words, the compressed video file is inside the folder of the saved DVD project. Can I just archive that on the external drive and be able to use those video clips in other DVD projects later. Or should I place the actual 35 gig file on the external drive?

What difference aside from space will it make? Pros and cons? ? ? What if I have more video intended for a later DVD and the files end up needing a greater compression to allow for the amount of video desired on the later DVD?

Thanks

Josh