Beyond CD's, your returns are less then guarenteed. There's something to be said for inefficient choices that give a great peace of mind(such as paying off a student loan and attaining freedom from seriously evil debt that bankruptcy can't even wipe), vs. attempting to place your money elsewhere.
Dave Ramsey, despite how wrong he is from a numbers perspective, is absolutely right when it comes to human emotion.
I vote for payoff the debt, pay yourself a little at the end as a reward, and then take the next steps forward into a financially controlled future.