Hey I am the one who started the Jesus Freak Forum! 
Any way no problems with taking offense or feeling somehow
uncomfortable with the term Jesus Freak! You are not the first
ones...even my own church leaders took some offense when I first
introduced the song in one of the gigs through my band in our
church 7 years ago. The song is called Jesus Freak by DC
Talk.
Laurence82 was right when he said the Jesus Freak is a 70s thingy.
In fact we knew the 70s is also known as the Hippies era. The Jesus
Movement are hippies who are christians and they called themselves
Jesus Freaks (but no, I do not think these Jesus Freaks engaged in
activities like drugs etc lah). Jesus Freaks is originally a
negative term along the lines of discrimination. But the people of
the Jesus Movement adopted that name. It is pretty radical and very
'rebellious' during that time to take on that name but church
history tells us that Jesus Movement at that time created alot of
news and were not accepted by most churches during that time mainly
because of its different thinkings and ways of doing things.
As the society changes, of cos the Hippies movement dies off and
with that the Jesus Movement also dies off. But DC Talk, a recent
christian band took up that name and wrote a song about it. And it
wants christians to understand that JESUS FREAK is not degoratory
but in the words of Toby, part of DC TALK, a christian who is "an
ardent enthusiast", among other things..so consider yourself an
ardent enthusiast of Christ!!
Anyway the music that was popular during the Jesus Movement period
came to us today as contemporary christian music with bands like
Jars Of Clay, DC Talk, Michael W Smith etc....
Thus Jesus Freak aims to be relevant, though it is not saying it is
the only way to reach out to people but it is one of the ways. As
we look at the society nowadays, it is important to be relevant in
your message. But hey I can understand why some of us are
uncomfortable. Just go the way that God has convicted you in, no
right or wrong as long we know God is pleased with us.
One Message. Different Language.
God Bless!