Gary Johnson isn't going to win. I don't think there's any question here.
HOWEVER, in my mind, voting Gary Johnson would be to make a statement, one that the Libertarian Party is gaining support.
I believe that writing-in Ron Paul if he doesn't get the nomination will have no impact at all in the long term future.
However, if we were to all gather around and vote Gary Johnson, and allow the Libertarians to break 1,000,000 votes for the first time, or break 1% for the second time, then I believe that this would make a statement, that there IS a third option outside the 2-party system we've grown up in.
I cannot vote, however. I can do nothing more that watch and cheer from the sidelines. I'll be watching, and rooting for Ron Paul if he gets the GOP nomination, or Gary Johnson otherwise, and maybe that makes me a bad person for not being a "NOBP" person, I don't know.