http://www.netbsd.org/MailingLists/ has info on the mailing lists.

netbsd-help:
            This list provides a general help forum where users can ask
            questions.

This says "general", so maybe non-NetBSD-specific questions are okay.
            
netbsd-users:
            This is a general purpose forum for all NetBSD users,
            regardless of platform. As a large number of subscribers
            receive this list, please use your good judgement when
            posting. Questions or comments about the maintenance or design
            of NetBSD itself, as opposed to issues related to using
            NetBSD, aren't appropriate to this list, and are better voiced
            in a more narrowly focused technical list.

This list description (though it seems a little unclear) says that
netbsd-users list is for "issues related to using NetBSD". So I am
guessing netbsd-help is the right forum for discussing miscellaneous
topics such as using GNOME and KDE.

If it is not, then maybe someone should start a netbsd-misc,
netbsd-general or netbsd-chat forum which can be used for other random
discussions.

Or maybe a mailing list for netbsd-gui which can be used to discuss just
this. (But then again, this is getting into maybe too many lists.)

   Jeremy C. Reed
                                      FAQs for ISPs
                                      http://www.isp-faq.com/

p.s. I am writing some articles introducing open source; I hope to have
some local examples. If you know of a Puget Sound- or Pacific
Northwest-area company or organization that uses BSD or open source
software that I should interview, please let me know. Thanks.