No experience editing HD camcorder footage, so I’ll leave that one for someone else.
To back up blu-ray movies you’ll need AnyDVD HD to break encryption and rip to the hard drive. It is the only program that is currently available that is effective against BD+ protection. If you want to make a full backup, you can rip as an ISO file and then burn to a blank blu ray disk of the appropriate size with ImgBurn using UDF 2.5 file system.
AnyDVD HD is not free, but there is a free 21 day trial to test it. ImgBurn is free to download and use.
Many commercially made Blu-ray movies will be in the 30-40gb range in size, so you’ll need the more expensive 50gb disks to back them up. Some are smaller, but few full backups will fit on the 25gb disks.
It is possible to do just the main movie on the backup. You can rip as files, then use tsMuxeR to select the main movie and output as a Blu-ray movie. Even selecting just the main movie often times gives you more than can fit onto a 25gb disk however.
There is one program out now that can compress the movie to fit onto a 25gb disk, either main movie only or full backup. It is called BD-Rebuilder. It is free to use, but it does not include a decryption program. You still need AnyDVD HD to decrypt and rip the movie to the hard drive first. And you should be aware that encoding HD video is very intensive work for your home computer. Even with a quad core machine, you’re looking at overnight encoding times. With my Core2 Duo dual core machine, it takes 16 hours to reencode a blu ray movie.