Personally, I would do a mix.
Pay off the 4.29% loan now, or as soon as it starts requiring interest payments.
Do you have enough deductibles to actually deduct the student loan interest? If you take the standard deduction, that wouldn't be a consideration for keeping them (but, I've had Schedule A deductions since I was 19, not sure you can take them without that, and other factors that go with it--house, dependent, etc.)
What is the payoff time for the rest? I might not try hard to pay them off, but I'd round up the minimum payment and make sure the extra is going to principle.
Then I'd start investing with the rest.
Other factors that may influence things-- do you plan to buy a home? What is your credit score like if you do?
Sounds like you're off to a great start! Starting young is a huge factor when it comes to compound interest.