New England - Which one day Boston tour is recommended?

Received great advice so far so here's one more question.

Today we plan to tour Harvard. Then we have one full day left tomorrow.

Is there a one day tour that's particularly recommended? Value for money, extensive, informative? Any that offers student discount?

Duck boats are fun, but are pricey, crowded, relatively short, and not too educational.

Hop on hop offs are much more flexible and educational.

I couldn't tell you one from the other, though (there are multiple vendors)

Out of my Element is right. Duck tours are a fun high level tour but not the most expensive option. Will not take all day though. One other option to add is taking a Freedom Trail tour. They will offer a student discount. A Fenway tour might be an option but with the 100th anniversary going on will probably be crowded.

The Trolley Tours (http://www.trolleytours.com/boston/rates-and-reservations.asp) in Boston are expensive, more than the duck tours which we didn't do. But we thoroughly enjoyed ours when we did it many (~20) years ago when I was still a teenager - just - and we also did one of the major museums that afternoon. I've just checked and it is cheaper if you book online and they do do a student discount, plus the ticket is valid for the next day as well.

The Old Town Trolley cost about 175.00 for a family of four. If you have a day, take the free walking tour that starts at Boston Commons. It lasts about 2.5 hours and was one of the best city tours I have ever been on. From there you can go to Faneuil Hall, the ranger service has guided tours as well. Don't miss the military museum on the fourth floor.

If you have two days in the future, the Trolley Tour was well worth it.