Long-term backup storage media

Hard Drives. Space is dirt cheap these days, you can grab a few TB worth of internal hard drives at a fairly low price. Even external hard drives aren't too expensive.

Regarding longevity, you'll probably accumulate data too fast for the media to be a problem. 7 years from now you might have enough DVD's to fill a couple Blu-rays. 7 more years and you'll have a stack of Blu-rays ready to consolidate on whatever the next big thing is.

For now, Patrick McFarland's How To Choose CD/DVD Archival Media comes out in favor of DVD+R, specifically Taiyo Yuden's:

To begin with, I do not recommend CD-RW, DVD-RW, or DVD+RW media in any form for permanent storage. This is mostly a no-brainer, but those discs are meant to be able to be changed after burning, and they are simply unsuitable for long-term archival storage. I also do not recommend DVD-R media due to DVD+R’s superior error correction and burning control.

That said, I recommend Taiyo Yuden media across the board. Taiyo Yuden currently manufactures 52x CD-R, 16x DVD-R, and 8x DVD+R media in normal shiney silver, inkjet printable, and thermal printable forms. Taiyo Yuden may be one of the most expensive (if not the most expensive), but their media quality is unsurpassed.

A recent update shows he still affirms this position.

I thought I read somewhere that the Library of Congress uses MAM-A archival gold DVD's but considering the cost I stick with TY's. I usually purchase through http://www.rima.com, while McFarland recommends another vendor in his article.

Rumors say CDs and DVDs won't remember your data longer than ten years.

You just said it: RUMOURS! :)

The Optical Storage Technology Association (OSTA) has published the following longevity estimates for recordable optical media:

Manufacturers' estimated recorded life span.

CD-R: 50-200 years

CD-RW: 20-100 years

DVD+R: 30-100 years

DVD+RW: 30 years

BD-R 50+ years

So, chances are that you may not live long enough to prove these estimates wrong! :)

Now compare that to the average lifespan of a platter hard disk (2-10 years). Optical media win that contest hands down.

And then there is the good old stone tablet which will last a couple of thousand years. But the data density of 0.001 kbit/kg is a bit of a showstopper. :P

But in IT, the Cranberry Diamondisc DVD is considered to be the Holy Grail of long term storage, they boast a life span 1000 (one thousand) years. Of course it requires special hardware to burn these discs.