Pay down student loan debt or invest?

We have a lot of student loan debt. If you look at the sidebar you will see that I am not joking. While there are a few private student loans in that mix, the majority of the loans are the super low interest rate ones. Currently the highest rate on the private loans is 8.00%. And our lowest student loan rate is 2.65%.

I was doing some thinking recently about all of these student loans and their interest rates. And then I was thinking about how you can get 8% or better return on some mutual funds. With that in mind, it seems to me that any extra money that could be applied to paying down student loan debt would be better served in a mutual fund with a good track record. I would think that as long as you are earning more than the interest rate on the student loans that you are coming out ahead of the game.

Is my logic flawed on this? I mean, sure, you could have a bad year with the mutual funds and not only make less than the 8% but even lose money. But still….it seems logical to me.