In Debian and Debian-based distributions (such as Ubuntu), Samba requires several packages. samba is the package that sets up a SMB server. It automatically includes samba-common, which is also needed for SMB clients. smbclient is a command-line SMB client that is very useful for debugging and testing purposes. smbclient is somewhat similar to the command line version of ftp.
Disk space allowing, samba-doc can be a useful addition, though not necessary. This package includes detailed documentation of how to set up samba, and even a bit of information regarding how SMB itself works.