Anyone planning on voting tactically, not for favorite candidate?

[rob in cal]

There are a few Governor and US Senate elections in which there are three main candidates (polling in double figures) in states as diverse as Maine, Florida, Minnesota, Colorado, Alaska, Massachusetts and Rhode Island.  I'm wondering if people on this board are grappling with the issue of whether to vote for their favorite candidate, or the one most likely to defeat their least favored candidate.  In UK elections this happens all the time, as three way election battles between Conservatives, Labour and Lib Dems is the rule.
    Personally, I'm probably closer to the Libertarian candidate for US senate in California than to either Boxer or Fiorina, but will most likely vote for Fiorina as she is within striking distance of victory (though I'm not expecting her to win).