It kind of depends on who much data we are talking about.
Keep in mind you will have completely update all of your data when formats change and evolve.
I still have some photos on floppy disks that even if I bought a floppy drive I would have to find a windows 98 system to run the program to view them. I also have some photos in .ufo format that was a ulead program. So you have to keep updating all of you data. It will never end.
If you dont have a ton of data puting it on a external hard drive AND then copies to DVD's is a solution. I have external drives redundant in storage so that even if the house burns I still have (most) of my photos.
I am not talking about western digital or walmart drives Those will fail not if but when.
While I was in photography school we had about 30% complete drive failures on that type of drive in three months.
I know an indi film maker that recommended CalDigit drives. They were going through terabytes of data every day with no problems. I have used mine for 5 years now as a daily working drive and have others for permeant redundant storage. (check amazon)
Lots of people are going to "cloud" storage while I see the attraction of being able to access the body of your work from about anywhere I am leery of having my work out of my control, hacks aside, I have seen photo storage site go out of business with little or no warning. Remember yahoo photos? My employer has some of its storage on flicker for public access to the photos. I have noticed in the last two years that there have been increasing issues with flicker that I think have to do with it falling out of favour with the younger users, and that means less money in and less money for upgrades and newer servers. One day it wont be profitable and it will go away.
OK, long answer there, so buy a good external drive. buy as large and as new (fast) as you can and your computer will handle. Use it for your archives. have a second day to day drive that you transfer data from it to the archive drive. Once the archive drive is full move it off site.
Start again.
When the formats and software change, convert them all again. or be sitting on photos in floppy disks.
SSD (solid state drives) seem to be the next wave, but are to expensive right now. Two years or so from now they will be the new normal.
