An entire major in business -- more than just a handful of courses and books -- isn't particularly useful, and even if it is you can get an MBA well after graduation, as most MBAs do. I wouldn't spend time on it now. You're better off with tennis.

I sometimes wish I'd taken more economics courses than I did (which is to say: none whatsoever) but don't make the mistake of majoring in economics with the idea that it's kind of like business. That would be like studying reproductive biology because you really like kids. Economics is about constructing highly abstracted mathematical models of poorly understood phenomena. It has potentially difficult math in it, which makes it hard, which is good: Your college major should challenge you. But it's not about building things people want. Unless your definition of "people" is "other economists".

If you want to help build complex stuff (which is what many startups do) take courses which are about building things. CS is a fine thing. Any form of engineering is a fine thing. Courses which make you write or speak are a fine thing. Courses which emphasize data gathering and analytics -- statistics, sociology -- are a fine thing. And, since building stuff often requires knowing how it works, sciences are a good thing. I don't regret having taken the hardest science courses I could stand.

(It also turns out that it would have been a good idea to study art.)

But the sad truth, for those of us who loved school, is that formal schooling need not matter that much. Building things is as much about practice as theory. Go build a website right now, in PHP and MySQL on a Linux VPN in the cloud. Or download the Stanford course on iPhone development and build an app right now. Don't let school and sports become some kind of excuse, as if you needed some kind of prerequisite or badge or four-year degree to start building things. Start the habit today.