diversify
some in a local wallet, some in a cloud wallet (mybitcoin or instawallet, and other sites like witcoin or youtipit) and some on an exchange.
see the article about setting up a secure btc savings wallet with truecrypt.
Good idea tbh, I suppose doing it that way prevents you from losing everything if you do get your wallet stolen or account hacked. Already got my wallet encrypted just in case though

Going to follow this idea too, thanks.