It might be interesting if you could store the blockchain and wallet.dat on a rewritable bluray disc instead of your hard drive. Then you could simply use bitcoin from any device that accepts bluray disks and bitcoin.
Exactly my thinking...
Hard Drives fail and burn out.. but if you keep a disc in a nice sleeve it will last forever.
That way it would also be alot easier to physically store your bitcoins.. rather than a decaying thumb drive; a stack of blurays!
Its my opinion that any online wallet or computer wallet is at a huge risk and you would only use those as a buffer between your bitcoin use and bitcoin storage
Idunno about Blu-ray discs specifically, but CDs are not long-term storage devices. After 5-15 years, there will start being significant issues due to degradation (even if you don't use them). You'd end up with corrupt, unusable data in not-so-long - likely without any warning if you don't regularly use the disc you're storing whatever on. Again, I don't know about Blu-Ray discs specifically, but it seems like a terrible idea to store your private keys on a disc (HDDs obviously included) without backups.