most flexible solution is using your PC with a DVD burner. to make 1:1 copies you'll need two banks when copying dual layer DVDs. you can also wait for dual layer burners which are just about to come. I hope there won't be any compatibility issues with stand alone players. also dual layer blanks prices may be of concern, especially at the beginning.
An alternative is to use something like DVD Decrypter to create an ISO o your hard drive and store them there. Then, when dual layer burners and disc blanks become commonplace (affordable and reliable) you can burn the ISO to a disc.
You could also burn it now on one DVD (reduced quality) or split it across 2 DVD's as stated above.
A dual layer DVD will be around 8 - 9Gb each. Obviously most disks also hold extras (DD2 & DD5.1 & DTS 5.1 sound, other languages, documentries etc) that you might not want to copy to your HDD, so this would save a fair bit of space.