Entry for "www"

[Jim Picerno]

Could someone provide an example of an entry for ""www.<domainname>.com".
More specifically would you use

web.<domainname>.com.    IN     A    1.1.1.1
www.<domainname>.com.  IN    CNAME     web.<domainname>com

                                or

www.<domainname>.com.    IN    A    1.1.1.1

                                or something else?

thanx