Libertarians have always been divided into BIG L libertarians (i.e., members of the Libertarian Party) and small l libertarians (i.e., believers in libertarianism as a philosophy). Most libertarians are found outside of the Libertarian Party for several reasons. Most importantly, the Libertarian Party is extremely ineffective and is the province mostly of people who place ideological purity over getting things done.
Thanks in large part to the fusionist movement of Frank Meyer and the early National Review, libertarians are usually associated with the conservative movement, and hence the Republican Party. I for example, have only rarely voted for the Libertarian Party, and usually because the GOP candidate was extremely odorous.
Steven Green of Vodka Pundit (who I suppose will be dealing with the upcoming Clinton Administration the way I plan to) blogged on why he is no longer a Libertarian (though presumably still a libertarian). Glenn Reynolds noted the essay on Pajama Media and pretty much said he felt the same way. This leads to a bunch of other confessions, and Andrew Sullivan blame the lot of them for destroying liberal democracy in America by supporting Bush (OK, maybe a slight exaggeration). Green posts his reply, explaining the difference between Big and little "l" libertarians.
I have always been a Republican, even as my political philosophy has drifted. I have never been a member of the Libertarian Party. While I wish them well, I view them basically as an out for people like me to indicate my displeasure with the GOP. My main problem with the Libertarians goes back to college. It seemed that self-described libertarians were more interested in fighting arcane inter-fraternal philosophical battles rather than discussing real world policy choices. It is like when back during the Nixon Administration, Milton Friedman found himself in conflict with libertarian leaders such as Karl Hess III because Friedman was more interested in guiding policy than fighting losing battles.