I wouldn't trust keeping any coins on blockchain.info. They've had serious security issues lately. If you have a lot of coins, put them in cold storage. Meaning, get a hard drive, encrypt it with TrueCrypt (optional), install your wallet on there and keep copies of the wallet.dat file on some other flash drives as a back up, and keep that hard drive disconnected from the Internet. That's it. You can always check the balance of the wallet by checking the address that holds the coins on a block explorer site (blockchain.info is good for this).