I graduated pretty recently, but I can tell you what I thought was most helpful.

-Lots of language exposure. Take classes in different languages (classes comparing languages are even better). I find it difficult to learn new languages, particularly new paradigms, without the help of someone who knows them.

-Low-level stuff. Assembly, basic electronics, C. These are the topics I found classes covered the best (compared to learning on my own). It's not directly relevant to my job, but I just have a generally better sense of how computers work.

-Work in groups. I didn't do enough of this, and I think it handicapped me a bit. This is less applicable to you than to most people entering college, since you are presumably doing that at your startup.