Guys, just to wade in on the longevity of digital storage, I think some of you have drastically missed the point.
First of all, briefly to qualify myself, I'm an IT director of substantial qualifications and experience and have directed and worked in data recovery over the years as well as having muchos first hand experience with backups, lost data, old data and so-forth. I'm also a competent programmer and understand all of the technical issues with long term digital storage, both software, firmware and hardware oriented.
As everybody knows a DVD, CD, floppy or hard drive has a very short lifespan. If you dump a load of images onto a DVD, don't expect them to be retrievable in 40 years. Heck, from my experience, give it 3-4 years and you're on dodgy ground.
But! This misses the ENTIRE point of digital.
Nobody would do that, unless they were entirely lazy or foolish. Instead, what you would do, is to keep all of your pictures on your computer in a folder labeled 'Pictures' (and presumeably within subfolders therein). Fear not, it won't "Clog up your hard disk" or "Slow your computer down", you have my assurances, and even in 15mp RAW files the space is cheap as chips.
Every time you buy a new computer, so the Pictures folder comes over with you. And once in a while you back it up onto an external HDD or somesuch, which you update once in a while and keep safely elsewhere.
And so the cycle of preservation continues, so that your Pictures folder goes with you for the rest of your life, hopping from one medium and computer to another, being copied to new filesystems as they emerge, never degrading in quality, always backed up, copied here there and everywhere.
JPG will not become unreadable in future because we 'forget how the format works', as some silly people suggest, and if at some point a superior format emerges, well you'll find it's a click of a mouse to convert thousands or millions of snaps to this new format.
So go easy, digital storage is indefinite, flexible and brilliant. If you don't back it up, then at worst you're in the same boat as film - a lost folder could mean lost pics.
Do back it up, and I see no reason your images won't last till the end of human civilisation without loosing a pixel - The only way film can achieve that, is if someone scans it.