Aaah, the memories. As a father of five, I have quite a few. Of course the most common way to preserve memories is the good, old fashioned picture. My oldest has a library of "baby's first year albums," professionally produced video (on VHS) slide shows, and countless mementos from a framed locket of hair to an urn full of baby teeth (which I find somewhat disgusting). Number two has the same things, but in smaller quantities. Numbers three and four have NONE of those trappings, just various appearances in old (VHS) videos and the standard smattering of snapshots sitting in a shoe box marked with their names. Yes Virginia, it still sucks to be born later down a line of siblings if you want baby memento swag.
But a funny thing happened on the road to adolescence for numbers three and four; somebody gave daddy a DIGITAL CAMERA! No more film to develop, no more rationing shots so as not to run out of film. This is daddy nirvana.
Two terabyte external drives later and we have tens of thousands of pictures of everyone now. Every Christmas, grandma gets a "year in review" photo collage, loaded by thumb drive, onto her LCD, electronic picture frame. There are plenty of pics of everyone now, because a huge cost and convenience barrier have been lifted. Barely a day goes by without a picture being snapped, so it's real easy to build up a nice year in review collection for electronic frames. Just make sure you back up all your pictures on external drives- we keep ours in a fire safe!
The biggest beneficiary of emerging technology is the seven year old (affectionately called "Little Miss"). Not only does she have a plethora of photos and videos of her, she posts them on her own website! She even "stars" on my site sometimes.