I turned to the dark side eventually and got an MBA...worked in research on financial markets...I got to do some financial/economic history along the way. Studying history taught me so much: how to do research; how to analyze; how to create an argument and support/defend it; how to write a paper...I used all that in my career. Also if you work internationally, knowing their history can be a big plus.

For a successful career outside of history after majoring in it, it certainly helps to have graduate training in whatever non-history career path you choose. If you like to teach, then history may be a good path on its own. My problem was that I didn't enjoy teaching that much and you need to love it to make it through, to make history your life work.