One of the interesting topics that came up as I was listening to old episodes of I Should Be Writing was what is a good college degree for a writer?
First, I think you should be thinking about what job you're going to have while you work toward being a full-time writer, if that's what you want to do. Only a fraction of a percentage of writers will get to be full-time writers right out of the gate. The vast majority of us need day jobs, and you should plan your major around whatever is going to pay your bills. If you don't expect your college degree to have anything to do with your day job, skip college. It's nice, don't get me wrong, but it's a whole huge ton of debt that you are going to have to pay back. Save yourself tens of thousands of dollars and several years of your life and go to Clarion or another workshop instead.
However, if someone else is paying for you to go to school, or if you're going to school for one thing but want to maximize your electives with writing in mind, here are my thoughts. Focus on classes that teach things or offer experiences you can't readily learn from books. Books are cheaper than college courses.
Psychology: I got a psych degree because it was the thing I was closest to finishing when I realized I had no idea what I wanted to do with my life. As far as WTF degrees go, it's a good one; people think that it means you might be good at dealing with people. After all, that's what HR people get a lot of the time. It doesn't actually mean that you're good with people though. What a psych degree will do for you is give you some insight into why people are so screwed up, and some of the ways that people are screwed up. (What you do with that knowledge is, of course, up to you.) This can definitely be useful when developing realistic characters or when you want to manipulate your characters in a realistic way. Get yourself a broad look at psychology—-behavioral, cognitive, developmental, psychoanalytic, all of it. All of the models have their strengths and weaknesses, and since you're just a writer, you can pick and choose all the interesting bits. A lot of psych can be learned from books, but not a lot the really neat stuff, and all the really interesting classes require you to take the beginning classes anyway. (I'll start preparing you now: correlation does not equal causation. Say it with me.)
Folklore: I was one class short of accidentally getting a certificate (roughly the equivalent of a minor) in folklore, so like with psych I'm a little biased. However, folklore is the study of story. I think it's hard to go wrong with that. The way my teachers all looked at it was that history was the study of what actually happened, and folklore was the study of what people believed had happened, and why they believed it, and what it meant to them. Folklorists don't care about what the facts were. They care about the story; why the story is interesting, how does the story change or remain the same from culture to culture, audience to audience, generation to generation. You will learn a lot about good storytelling by studying folklore, as well as get familiar with the plot and character archetypes that you'll use again and again as a writer. (Please note: pretty much all of my folklore professors had two jobs. There is a reason that was not my major.)
History: There are so many interesting stories out there that studying history can be a great way to start as a writer. Many authors have built fine successful careers out of writing historical fiction, and others have been inspired by past events into creating wondrous works in all sorts of genres. I only took one history class in college, but I wish I'd taken more. Still, history is one subject that is very easy to study outside of the classroom. Go for the hands-on sorts of classes, or at least ones with discussion groups.
English: I avoided English classes like the plague when I was in college. I regret that a lot; I probably could've shaved a few years off my learning curve with the right classes. However, in those years I was not ready to learn about writing from other people: a few bad experiences in my high school writing workshops led to my belief that letting other people "tell me how to write" would turn my own original work into someone else's Frankenstein. As with so many other things, I had to grow out of my early 20s before I was able to realize just how much I didn't know. You can learn a lot about writing from books, but nothing substitutes for one-on-one time with a really good teacher. Individual feedback is key. With that said, I will point out that a bad teacher can turn you off from writing—-avoid them at all costs. If you have to ask, it's worth dropping the class. Also note that a hard teacher is not necessarily a bad teacher, and vice versa.
Art: I recommend taking at least one basic drawing class. Artists look at things differently: they learn to see what something really looks like, and not what we think it looks like. This useful skill can be applied to all sorts of things. You can also develop this skill by studying philosophy, but it's a lot more straightforward in art. Which is funny, considering how much symbolism is in art—-but then, manipulating symbols (theme!) is a handy skill too.
Phy Ed: Stay active. Writers are a sedentary lot. Some of my favorite college classes were fencing (sabre and theatrical) and Relaxation. Of all the classes I took, I probably use the knowledge I got in Relaxation the most often. (Although Psychobiology of Stress and Coping is up there too.)
There are probably lots of interesting sociology classes and anthropology classes and biology classes and hard science classes that would also be good for writers, but I didn’t take any of those. I did take some in high school and later through the Teaching Company lectures. (I'm desperately hoping my library gets a copy of Impossible: Physics Beyond the Edge soon!) If you find something interesting, look into it. Study broadly. Read a lot. Having a wide repertoire of knowledge will give you lots of idea nuggets that you should be able to combine into interesting stories.