Your options are bountiful (SAT word of the day!), but it's hard to determine exact numbers, because it depends on other things:
1) Will you have other debt? (undergrad? credit cards? mortgage? etc?)
2) 10 yr repay, 15 yr repay, 20 yr repay, 25 yr repay? (These are your options...some consolidated loans offer 30 yr)
3) You can (as of now) defer your loans during residency for economic hardship. This means your subsidized loans do not accrue interest, and your unsubsidized will accrue, but you wont be saddled with a big residency payment. Furthermore, some companies allow you to stagger payments so that they are purposefully light in residency. Laws of economic hardship have also recently changed (last month!) and will be different in 2009.
4) Interest rates. Federal student loan rates are currently fixed at 6.8% for the life of your loan. However, with current fed pressure because of the economy, there is talk student loan rates may drop also. For now, plan on 6.8%.
5) Use a loan calculator:
http://www.ed.gov/offices/OSFAP/DirectLoan/calc.html
6) Will you still love Peds as a third year clerk? If not, and you fall in love with say, Radiology, let's face it: repayment is much less of an issue. If you decide to do a peds fellowship? Now, for some fields (cards) $150k can become $200k or more.
7) Your med school will have a financial aid office and AAMC requires you to have an entrance session about loans (likely during orientation), and an exit session (sometime during your 4th year). Talk to them to find out other options.
No worries for right now though, celebrate getting in!! Worry about this in a little while...