Yah, I used the big L there. I suspect that self-identified libertarians are a big chunk of the Republican party. Together with conservatives we might just be a majority of the base. : )
However, we just keep accepting the dunderheads the party feeds us as candidates. Mel Martinez. Ptooooi!
Terms like "conservative" and "liberal" are politically relative. Terms like "libertarian" and "socialist" are absolutes. To the degree that our founding principles are libertarian, libertarianism is conservative.
I've always considered myself libertarian, but I've always voted straight party republican in every election in which I've voted. Unfortunately the republicans don't seem to be a very attractive alternative to those of us who desire to see a smaller federal government and promotion of individual liberty.