I've never self identified as a libertarian precisely because of the difference in attitude I have regarding their approach to foreign policy. Its my biggest beef with them.
Domestically, I trend towards libertarianism on social issues, but economically I am not quite one. Things like returning to the gold standard are going to be a bit outdated and not feasible IMO.
Overall, I think libertarianism is an ideology just like any other. In its purist form, it just won't work. Thus variations of it spring up. Its kind of the counter to Marxism, which is full of its own "faux-intellectuals" as NCFY so eloquently regards libertarians.