Leveragecard.com will register all of your gift cards and track them for you -- for free!  You'll even earn interest while they have a balance!  (OK, it's only 1%, but it's something.)  They can replace them if you lose them, tell you what the card number is so you can use it online (even if you don't have the card with you), and notify you when the balance changes.  Here's the complete list of features from their website.

• Earn Interest! Even on cards you don’t receive through Leverage you can earn interest simply by registering your cards*

•  Remind yourself  which cards you have

•  Know the balances on your cards

•  Backup Mechanism to retrieve card numbers

• - When you lose a physical card

• - When you don’t have the card with you but you want to shop online 

•  Get notified when your gift card balances change

• - Know if you are losing value on your cards due to inactivity fees

•  -Learn about fraudulent activity right when it happens

•  Registering gift cards also helps you to attract the right offers  and communication from the appropriate retailers with the Transparent Targeting mechanism

•  Enter the Leverage Gift Card swapping environment whenever you decide you would rather have a gift card from another retailer

They can also track all of your loyalty programs, such as frequent flyer miles, hotel stays, etc, by notifying you when your balance changes positively or negatively.

I just registered all my cards with them and I urge you to do the same.  (Although I'm not sure what it will get me, it couldn't hurt to put my email address as the referrer.  That's curtis - at - backupcentral.com, thank you very much.) ;)