Yes, Slackware still comes with xv, Java(*), official trademarked Firefox binaries(**), an mp3 coder/encoder(***), and probably some other gratis-but-not-Free software. That doesn't mean you have to use them. All of the non-Free components are entirely optional and it's perfectly possible to have a 100% functional Free-as-in-speech Slackware system.

(*)Yes, Sun is going to open-source Java but I don't think they have, yet, and in any case, Slackware ships with a proprietary, closed-source version.
(**)At least Debian says these trademark restrictions make Firefox non-Free and they have renamed their custom-compiled Firefox to Iceweasel in their distro and derivatives, such as Knoppix.
(***)The mp3 format is patent-encumbered, so purely Free-as-in-speech distros cannot play mp3 files.

- Martijn Dekker, Groningen, Netherlands