Don't get on a 20 year plan to pay it back.
Why?
I had all federal Stafford loans, but was feeling the "ouch" of a high monthly payment. So I refinanced mine in 2009 after 4 years of paying, skating in just over the minimum ($20k in debt) to qualify for the 20 year plan. (My next payment would have dropped me below $20k forcing a ten-year repayment cycle, so I'm glad I refi'd when I did.)
Tripling your repayment term doesn't do much for saving on interest, but that loan debt is the cheapest debt I have by a long shot (4.25%

and my monthly payment is now less than what I spend on... well... a lot of things, actually. Definite improvement to quality of life and general stress level, and there's no early-payment penalty, so if I really felt like it, I could throw extra money at them and pay it off sooner.
To the OP: talk with a finance guy, figure out what your average yield on your investments and savings will probably be. That's your magic number. If you have debt at APR that's higher than that number, pay it off asap. Lower? Put the money in savings/investments instead.
Also, up to $2500 in student loan interest is tax deductible.