[DennisP]

Here's an article by some cryptocurrency researchers, about a proposed anti-theft extension to Bitcoin: http://hackingdistributed.com/2016/02/26/how-to-implement-se...

The same scheme can be implemented as a one-page smart contract on Ethereum: http://www.blunderingcode.com/ether-vaults/

Of course Ethereum had its own giant theft, but that was from a convoluted, poorly-written, and much larger contract. There are ways to avoid the sorts of vulnerabilities that were exploited there: http://www.blunderingcode.com/writing-secure-solidity/

Probably other vulnerabilities will be discovered. But I think simple contracts that secure ether with multiple keys, timelocking, and so on are a pretty good solution for anyone just storing and sending ether. They're also starting to incorporate formal verification of contracts; the online Solidity compiler includes it now, though it doesn't yet support all Solidity features.