Well, this morning I thought of something obvious (maybe not so obvious, or I'd have thought of it before) to do with this newfound pit of free storage space. Maybe it's been posted/suggested before, I didn't check.
Like lots of people, I'm out and about on a regular basis and carry a wallet. It's not out of the realm of possibilities that, under certain circumstances, I could come home without that wallet (I was going to say, "these days, ya never know.... blah blah", but actually it's always been true).
If I were to be parted from my wallet, I'd want to recover the things I have in there (not a whole lot but there's a reason why I carry what I have) and would want to recover them where possible. So making a list of the wallet contents (while I still have it in my hands) would at least be a start.
I wouldn't be stupid about it (no CC numbers or anything), just "Visa, Amex, insurance.." as a memory jog for reference that'll hopefully never be needed. But the "cloud stuff" is available anywhere (even offline, at least in the case of Google Docs).