Although I have some strong differences with Johnson, I'll probably vote for the Libertarian candidate in 2012 for two reasons:
1. GJ won't be elected. I have a couple of large differences with GJ that I don't want to see this Libertarian candidate pursue. The Libertarian candidates would be WISE to relinquish their positions on seeking governmental support of homosexual marriage (private affair) and support for abortion.
2. An alternative to the Democratic and Republican candidates for POTUS needs inclusion in the presidential debates. The general election of 2012 is a very good opportunity to seek the inclusion of the Libertarian voice in the presidential debates in 2012.
I feel fairly safe in voting for GJ in 2012 since the probability of him winning is nearly nil and he has a fairly good chance of carrying 15% in a national poll & the general vote.