After reading all the great responses, I'll throw in my 2 cents:
- first of all, nothing is every 100% safe. If you back up to a CD or DVD, those can be scratched or even just render themselves useless for no reason at all (it's happened to me on several occassions with CD's I've burned at work; one day the files work fine, then one day they don't. Now way to retrieve them). If you store them offsite to a website, what happens when that site becomes bankrupt or whatever - are you going to be able to transfer 10s of thousands of pics somewhere else?
- second of all, do what is easiest for YOU. Personally I think the easiest is an external harddrive that is backed up daily or weekly via an online server somewhere. But maybe storing actual pics in a box somehow is easiest. Or scrapping them. Or only printing the best pics.
- third, organize what you have & organize as you go. No matter what, if they're not organized when you have time to do something with them, then you're having to spend a whole lotta energy figuring out the what, when & where.
It's an excellent question & thankfully there seems to be many solutions. I wholeheartedly agree with one poster, that if we think it's safe to keep them on our computers & we're going to sit down with relatives to look through them, we're only kidding ourselves. Hard copies are what people look at eventually.
Good luck!