creating .dvi/.pdf's w/ tetex 3.0

I compiled/installed tetex 3.0 and everything seems to be working the way it
should except the following.  No matter what I try to do, some .tex 
files will
create a .dvi file and some will create a .pdf file.  I'm not changing
\pdfoutput or specifying one type over the other.  What I'm expecting to
happen is that, unless otherwise requested, a .dvi will result in all 
cases.  But,
this doesn't happen all the time.  Is this because some packages are not
using \pdfoutput correctly?  I'm only using the packages that came with
tetex so I don't think that should be an issue.  If you have any ideas,
please let me know.

Thanks, Rodney