This may sound at first like a bad idea but it is very useful for people with rubbish connections (such as myself).
Get a large removable usb HD (> 40 gigs).
Go to a library, university or your mothers house and download the whole *-STABLE directory from the ftp (or closest mirror).
Since it is very hard to obtain a ports.tar.gz snapshot which is guarenteed to create packages to match the versions in your downloaded stable folder you might still want to go for the *-RELEASE packages instead.
Now you can install pretty much any application offline and if you do need a newer version, you can often get a newer version of a port and modify it very slightly to work with your respective ports collection. (in my case *-RELEASE) so all packages sync up to the ports collection provided on CD.
IMO dont bother with the DVD, it only has a relatively small amount of packages on it and most of those are for a desktop environment you don't even plan to use.