Name of App: iVault (free version limited to 10 cards)

Price: Free

Compatibility to iPhone/iPod Touch: Both fully compatible, although it's been made for iPhone in mind

Your own personal description of this App: Great for storing minor or major details about your purchased item (original stuff) like UPC code, purchased date, model, serial number. Those info are stored in someplace called 'Cards' and it does offers a lot of categories to choose from.

Pros:
- Simple and clean user interface.
- Offers a great variety of categories to create your cards, just to list a few: Contacts, Electronics, Clothes, Software serial number, etc... Never forget your password anymore!
- You can show off your collectibles with your friends!
- Ability to create custom categories for your cards, eg: Books, Robots, Portable Device, you name it.
- Backup your cards online. You'll need to purchase an account though. I don't think this is crucial. Well, it's quite rare for iPod to malfunction.

Cons:
- Some lag time (miliseconds) when tapping the button. It is a very minor issue though.
- In order to create more than 10 cards, it requires you to purchase the pro version, which is kinda expensive.

Personal User Rating: 8/10

Conclusion:
Definitely a nice app for storing details about your purchased collectibles, either for future references or showing others about them. Like your newly purchased iPod Touch.