Ideas for a nearly 100% reliable portable data storage

If 10 GB capacity is sufficient, then a 16 GB USB flash drive is the best solution in terms of robustness and reliability. A (synchronized) second stick, however, will double your chances to get your data home safely. :)

Have to wonder - why so much of your equipment is dying - environmental? Electrical(surge?) accident (drops?) or other? Your solution would have to incorporate protection against this.

Also, have you considered a remote solution - RDP into a system at home or possibly keeping things on the cloud? There are things like Microsoft Live Mesh.

Don't go with physical storage. Backup your data with Dropbox or to a server that is managed. Online space is pretty cheap, and you have full redundancy if they do daily backups.

If 10 gig is enough (and yeah, shouldn't it be?), borrow my procedure if you see fit : - 8 gig with all that data on USB-stick, hash and double/triple-check at will; one kept at each parent's house (this is of course something one has to re-adjust as one sees fit, in case no-one is to be trusted, two separate bank vaults would be my guess...hardcore though...)

Be ultra-prudent (parents do not live in same town as me, or each other (again....adjust as see fit))
and rigorous in regards to the what and the when and the where, stick to it; and you've got something that's kept me (a klutz of dimensions) knowing that my that is safe...

("that" seems to imply something....exchange with "my digital personification" or what-not...)

From what I've been reading you say, Paweł Gościcki, your main concern is not "portable" storage, but "encripting", "up to date" and "trusting services".

There are several points I'd like to address here, giving opinions and ideas. Sorry I don't really know any good ready solutions for it. But I guess some of them are available and others you may have enough frustration-power to build on your own.

For the breaking devices, even if you changed environment, I'd still bet it's some electrical issue - though it should not be if you really moved to far away. Removable media is more susceptible to static energy. If you are so consistent into breaking those gadgets you should really consider measuring more yours. I would.

For the "up to date", If I'm not mistaken, Dropbox (or maybe another service like Moby or Carbonite) actually is able to sync your files on your network without going to their server FIRST, so you really should give it a try as it would not consume your bandwidth. I haven't tried, but I think it would keep your 8GB chunk file in sync in your network, then you could use a second machine to open it up and sync to external media.

Even if there is no such option you could encrypt each file individually, rather than making that 8GB chunk that can't be easily synced. Get some script to first encrypt your files when you throw them in a folder and second throw them already encrypted on the Dropbox folder, or whichever. This won't be easy, maybe there's a solution already out there, but it's a simple idea to go around your issue. Of course, you couldn't backup your whole system like this.

And for actually using more portable devices, if you figure a service to use, or maybe using some sync software, you can get a second machine running with it and syncing everything you plug on it. That way you only sync your machine once with a device able to replicate external media at will, and easily.

Personally I just don't care about encryption. So I use the cloud, pen drives and time machine. Much simpler. :)

Hope I could be of any help.