I was a year old when my father was diagnosed with pancreatic cancer. At the time he worked at a hospital where they later named an auditorium in his honor; at his first diagnosis they gave him two to four weeks to live. After six months he removed his oxygen mask to die.
So here's my first suggestion: Don't record hours and hours and hours and hours of video. It'll be like the wedding movie no one watches, or the thousands of baby pictures no one looks at. Pick your favorite photos, have them printed into a hardcover book with iPhoto, and write down who is in them, what the event was, and why it's important to you.
My dad recorded about a twenty or thirty minute message to me on reel-to-reel tape. I sent it to a professional sound engineer to have it digitized a few years ago. I've probably listened to it three times in thirty-five years. I didn't understand it as a kid but it was amazing to hear his voice.
Every night until I was three years old I slept with a picture of my dad. At some point we accept and progress.
So, here I am as an adult and I have basically a couple items that were my father's: 1) The patch from his Air Force uniform with my surname. 2) In my bedroom, an 8x10 family picture with the three of us. 3) A shoebox with all the letters his mother sent him from the farm in the 1960s and 1970s. 4) That half-hour of him talking into a microphone, imagining his one-year-old as an adult and telling me to "find a beautiful girl and marry her."
No one cares about your material possessions when you're dead. Don't worry about sorting all your old possessions. Fill a small box with the most important items for your family and write down why they're important. And be realistic. I care immensely about the collar my dog had when she was a puppy; to anyone else it's a frayed blue ribbon for the trash can. My maternal uncles have spent a decade looking for my grandfather's original pilot's license from the 1930s with little concern for anything else he possessed; it's the records of achievements and milestones we cherish. I hope my college degree doesn't get tossed in the trash but expect every single one of my books will be quickly donated and destroyed, no matter how important that Oxford Dictionary or human anatomy textbook is to me.
So, all that aside: Your child has the advantage of knowing you today. So look back at your own life and the major events you cherish, and tell her about those. "The day I met your mother... so when you meet someone..." or "The day you were born was so important to me because... so when you have children..." Don't tell her about dating boys or finding a good job or reading books or traveling. Everyone figures that out on their own. Tell her about how important family is to you, and your connection to her future and her family as she experiences the wonder of life. Don't talk to her like a sixth-grader, you do that everyday already. Talk to her like she's 25 or 30 or your age. She'll understand your words when she needs to look back and understand.
Something positive can happen from the misfortune that has come upon your family. I understand life is precious because my father died when he was forty-two. So I've lived my life as if that's my expiration date: I've lived in New York City and Los Angeles. I've travelled to five continents. I've learned to sail. I've studied flight. I ride horses. I have a dog. I've spent well over a decade living at the beach because that's what I want. Every day is a gift and I live it like it's vacation. So many people have these simple plans: "When I retire, I'm going to the Grand Canyon and on a cruise around the Mediterranean." I learned from the death of my father to, well, it's a cliche, but seize the day. Do everything you want to do without fear because you might not ever get a chance. So consider your daughter might live a life greater than either one of you imagined only last year. Yes, it hurts you'll be apart. But I'd probably still be among cornfields without my tragedy propelling me forward.
And think about your wife too. So many people keep paying the bill on an old phone just so they can call it and hear the voicemail greeting for a dead relative. Your wife will soon be a single parent, terrified about working all day and paying the mortgage and mowing the lawn and lighting the furnace and snaking the sewer pipe and wondering what a soon-to-be high-school girl is doing between 3:30pm and 6pm while she's still at work. Never mind the immense loneliness resulting from the unexpected. Give her a thirty-second recording for those moments when she just wants to cry and laugh and run away all at the same time. Write her a letter that says, "Open in 2016." Just let her pick whether it's on January 1st or December 31st.
Finally, turn off your fucking computer and go take a nice trip together for a few days. We don't need a hundred hours of goddamned video, we need memories of love.