Hi Rob,
Sorry to hear about your loss, and your idea sounds like a nice tribute
Best bets would be to get yourself a wordpress install with a flickr plugin. Takes five minutes to set something up. Find a decent template from the wordpress template gallery and you're off.
Site can be edited, updated, changed by someone completely non-technical. YouTube vids are posted using the embed code (copy and paste) that youTube provides. Flickr gallery link allows you to include loads and loads of photos and albums without costing you on bandwidth (Flickr Pro is $25/year).
If you want some advice on getting this set up just give me a PM and I'll sort you out.
Cheers, Lloyd.