I've always believed taking out a loan for the simple sake of using it for your credit score is just a very dangerous and bad idea. I mean think about it for a minute, you are taking on debt when most people want to get out of debt. You never know what the future can hold, loss of job, unexpected medical expense, car repairs etc etc. If you don't need a student loan don't take one out or a silly personal loan.
I would take that extra money and either invest or put it in a high yeild savings account and store yourself up a nice nest egg/emerency fund. Save your money not give it away.
If you are young and have a credit card or two your credit will grow. I mean you already have said you have pretty good scores.
I just think taking on debt for basically no purpose is foolish and could potentially be a burden.