There are many applications now a days where smart card is used.

Computer security:

The Mozilla Firefox web browser can use smart cards to store certificates for use in secure web browsing

Some disk encryption systems, such as FreeOTFE, TrueCrypt and Microsoft Windows 7 BitLocker, can use smart cards to securely hold encryption keys, and also to add another layer of encryption to critical parts of the secured disk.

Smart cards are also used for single sign-on to log on to computers.

Smart card support functionality has been added to Windows Live passports.

Credit cards:

These are the best known payment cards (classic plastic card):

Visa: Visa Contactless, Quick VSDC"qVSDC", Visa Wave, MSD, payWave
MasterCard: PayPass Magstripe, PayPass MChip
American Express: ExpressPay

Cryptographic smart cards:

Cryptographic smart cards are often used for single sign-on. Most advanced smart cards include specialized cryptographic hardware that uses algorithms such as RSA and DSA. Today's cryptographic smart cards generate key pairs on board, to avoid the risk from having more than one copy of the key (since by design there usually isn't a way to extract private keys from a smart card). Such smart cards are mainly used for digital signature and secure identification

Financial:

Smart cards serve as credit or ATM cards, fuel cards, mobile phone SIMs, authorization cards for pay television, household utility pre-payment cards, high-security identification and access-control cards, and public transport and public phone payment cards.

Smart cards may also be used as electronic wallets. The smart card chip can be "loaded" with funds to pay parking meters and vending machines or at various merchants. Cryptographic protocols protect the exchange of money between the smart card and the accepting machine. No connection to the issuing bank is necessary, so the holder of the card can use it even if not the owner. Examples are Proton, Geldkarte, Chipknip . The German Geldkarte is also used to validate customer age at vending machines for cigarettes.

Health care (medical)

Smart health cards can improve the security and privacy of patient information, provide a secure carrier for portable medical records, reduce health care fraud, support new processes for portable medical records, provide secure access to emergency medical information, enable compliance with government initiatives and mandates, and provide the platform to implement other applications as needed by the health care organization.

Schools:

Smart cards are being provided to students at schools and colleges. Useage includes

Tracking student attendance
As an electronic purse, to pay for items at canteens, vending machines etc
Tracking and monitoring food choices at the canteen, to help the student maintain a healthy diet
Tracking loans from the school library