I have to respectfully disagree with what seems to be the conventional wisdom here. For the mustachian who will be mostly in a lower tax bracket at retirement, I think the straight numbers will typically dictate that filling up the 401(k) first makes you come out ahead, and paying down the loans faster is buying peace of mind, but isn't strictly the best financial decision.
Think about this: Your loans are at 7.3%, which is about the same as the return you'd expect from a moderately aggressive portfolio. So you should be basically indifferent between investing vs. paying down debt even before considering any tax implications.
And the tax implications of increased 401(k) saving will be significant.
This is what DW and I did this year and will do next year, as we are working to pay off substantial grad school debt at 6.55%: We have contributed to my employer's 403(b) and 457(b) until we get underneath the 25% rate. Since we will certainly retire in the 10 or 15% bracket (if rates remain the same), I figure that we have saved at least 10 cents on every dollar of tax-deferred income.
Just want to double check and make sure you understand how marginal tax brackets work, because from your first post it's not quite clear. Assuming you're filing as a single person, that 25% only applies to income over 36,000, after you take out your deductions. I just want to make sure you're not making the classic blunder of thinking that getting below that line somehow leads to a drastic jump in your total liability.
Not a drastic jump in total liability, but certainly a drastic jump in marginal liability. And if you have any taxable investments, landing in the 15% bracket gives you the advantage of being exempt from capital gains tax. Through some clever use of tax loss/gain harvesting, the typical mustachian should be able to avoid paying capital gains taxes almost entirely through this kind of maneuver. Alas, our 'stache is not big enough yet for this bit to be useful, but I am scheming for the future.