bunnybaby, depends on what you are backing up.
I would say the best media is DVD-R or CD-R and then archival grade, or for CD’s you want gold discs. Yes, they do cost a lot more but the data is safe for a long time, if you store the media in the right way. At least it will not degrade over time as standard media will.
So saving photos and such on gold CD-R, and video plus photos on archival DVD-R is the best option. Do multiple copies, oh and saving copies on standard harddrives good to. Forget flash media and such, will not do.
The worst part is saving video, takes up so much space. I find that only saving the most valued or important stuff is best, this way you keep the information to a minimum. Keep the stuff you have little value for, but still want to save on regular harddrives (that are in a cabinet offline).
A few years ago I dumped some old harddrives, real old, they where only the size of 120Mb or something, from the early 90s but guess what, they booted up and the information on them where readable.
As someone else pointed out, backup and storage is one thing, maintaining backups or archive is another !