Custom configuration for XBMC to use VLC for local video files only, and continue to use the built-in player for others.

playercorefactory.xml

<playercorefactory>
  <players>
    <player name="VLC" type="ExternalPlayer" video="true">
        <filename>/usr/bin/vlc</filename>
        <args>--play-and-exit --video-on-top --fullscreen</args>
        <forceontop>false</forceontop>
        <hidexbmc>false</hidexbmc>
        <hideconsole>false</hideconsole>
        <hidecursor>false</hidecursor>
    </player>
  </players>

  <rules action="prepend">
    <rule name="local-videos" audio="false" video="true"
          internetstream="false" filetypes=".*" player="VLC" />
  </rules>
</playercorefactory>