How safe is a brain wallet?
They can be made a heck-of-a-lot safer with simple key-stretching.  The WarpWallet runs Scrypt on your passphrase, and outputs a string in the full 256-bit keyspace.  It's at least 1000x more expensive to guess a WarpWallet address than a standard brainwallet address.  And if you had access to high-end scrypt-computing hardware, you're probably better off using it to mine litecoins rather than go after WarpWallets.  See https://keybase.io/warp.  There's a 20BTC challenge to solve an 8-letter WarpWallet passphrase that's been open for almost a month.