Running it from a isolated linux-based computer (A) that only connects to the internet to update/receive payments, otherwise, it is off and the HD is encrypted, Its wallet.dat file is encrpyted / hashed and backed-up on some remote server. (A) only receives payments by a second isolated other-linux-flavour-based-computer (B) that connects at the exact same time as (A). Now, you only deposit your savings to (B), which you have configured to automatically deposits everything to (A), during the short time where both systems are on-line.
Whenever (A) reaches a random amount of BTC (lets say between 90 and 990 ), the entire wallet.dat file is encypted, hashed and stored at 2 remote locations. A new wallet.dat is created. Your large sum of money will not attract any attention and you are the only person that knows the intricacies of your well-secured system. Nobody knows how many wallets there are. Nobody knows how much money you own.
At least, that's how I do it...
Why even have your "savings account wallet" online at all, EVER? Create an offline wallet.dat file, stick it on multiple offline media in multiple locations (encrypted if you prefer). So it's on 4 CDs and 2 USB devices spread out over 2 or 3 locations.
Anytime you want to add to your savings, send Bitcoins to that address, and verify the transaction in BlockExplorer.
