Your publication plans will likely depend on a number of factors including the funding agency, the purpose/aim of the research, number of journals publishing similar research, etc.
Based on my limited experience writing grants and attending grant writing seminars, I believe that funding agencies are likely looking for congruence between your publication plans and the rest of your application. For example, I received feedback from National Institutes of Health reviewers that my publication plans were insufficient, as one or two peer-reviewed publications was not congruent with the amount of money we were requesting ($100,000).
Thus, you might want to mention how the project will be broken into individual publications, when publications will be submitted, and anticipated impact. If you have space it may help to provide examples of journals that publish similar results.
Best of luck with your application!