What version of FCP? The terminology changed from ver 3 to 4, which impacts what you mean by "Movie" file.
Ver 3 and before, your Export choices were "Final Cut Pro Movie File" or "Quicktime Movie". That first choice (FCP Movie) gives you full quality with no compression, exactly what you want to use for a DVD authoring program. The QT option offered lots of compression alternatives, but at the expense of quality.
Ver 4+ changed those choices to "Quicktime Movie" or "Quicktime Compression". Their purposes are exactly parallel to what I described above; now the "Quicktime Movie" is the full quality option.
What you are doing (I assume it's the first of the choices) is correct if you have a relatively short (under 60 min) movie and using iDVD. For longer ones it's often necessary to do some fancy compression to optimize quality vs. disk space.
For a real answer, you need to give more info, such as OS version, FCP version, QT version and what DVD program you're using.
Scott