Things are better mixed up. I've always thought this and get irritated when forced to choose. My love of mixing things up is clear in my reading and viewing habits. For example crime = good; supernatural = good, hence urban fantasy supernatural crime fighters = excellent. Oral culture = fascinating; feminism = great, so feminist fairy tales are brilliant.
I think that's one of the reasons my qualifications are fairly broad, too. I studied Modern Languages - you get to do bits of history, literature and social science-y stuff as well as grammar and translation, you know - and then did a fabulous MA in Gender, Literature and Modernity which let me do modules from Women's Studies, English and Social History. They even let me bring MFL into it, so when we did Women's Writing from Africa and the Caribbean, I used some Francophone novels, and when we did the concept of the individual in eighteenth-century Europe, I was able to use some German. Brilliant. Things are definitely better blended.
And now, I have this very satisfying kind of blend in my career too. I'm teaching (secondary English, by the way) part-time in a school at the moment and writing and tutoring the rest of the time. I'm feeling really positive at the moment about what I can do and the possibilities I have. I'm balancing different writing projects, while also generating ideas and pitches for further work on a freelance basis and it's great. Interesting that this seems to be more of a 'thing' now. I just saw people discussing this 'portfolio career' model on my Twitter timeline yesterday (thanks @LynnCSchreiber, who directed me to to this interesting blogpost).
What do you think? Do you like mixing it up too? Are you a portfolio worker?