You might want to do a little more research on how bitcoin works.    


The bitcoins dont 'exist' in your wallet, they exist in the blockchain.  so your backup only needs the private key. not how many coins an addy has


edit:
My backups of my local bitcoin client from a year ago will still recover any coins in my wallet today if my puter crashed.

I may be wrong. But from what I understand if you made more than 100 transactions since your backup of the satoshi client you might not recover all your coins/ Most of the time a transaction breaks a previous one in two, sending some coins to the address you are paying to and some back to one hidden address in your wallet. Your wallet pre-generates 100 such addresses : once they are all used new ones that weren't backuped are used.

You need to make a new backup of your blockchain.info wallet every time you add a new private key (import or generate).  If you have it set up correctly it will automatically send you a new backup every time it is needed.

Never could get multibit to work....

Encrypted backup....

Google shows me the way -- will mess with it in the morning if not back online...

Did you follow these instructions?: https://multibit.org/help_importingPrivateKeys.html

Yes - the problems always came from downloading the blockchain.  Transactions wouldn't appear despite starting the replay from the genesis block.

Hey, I've met with an error when I tried to send some coins from an imported privatekey. It says 'No free inputs' although that address has enough to cover the transaction. I've tried to manually send the tx via pushtx, but the transaction does not show up in the blockchain. I had to import the key to Electrum to get the tx sent out successfully.

Don't follow their twitter stream...

Thanks!