Best suppliments or minerals to take for optimum health?

I'm pretty fit. Want to do everything I can to sustain my body's health for as long as possible. I'm already on a pretty healthy diet, I very rarely eat fast food and watch my fat intake.

So hears the question:

I'm not one of those people that wants to load up one 10 different supplements. I'm rather simple. Basically, I'm looking for a minimal mix or vitamins/minerals/antioxidants. Right now I'm taking a multi vitamin and omega 3. I feel like this pretty much covers all that I need? Any advice for more? I don't want to overload my body with any particular vitamin/ mineral. So please do not suggest something that will double a particular vitamin/mineral.

Thanks!

(21 year old male, 5'6", 143lbs.)