Check out changelists, which can provide you with an option to filter out files you have changed but do not want to commit. SVN will not automatically skip a file unless you tell it to - and the way you tell it that this file is somehow different to other files is to put it in a changelist.
It does require more work for you, and you can only apply the changelist to your working copy (obviously, imagine the chaos that could ensue if you could apply a 'never update' property to a revision!).