I stayed at La Reserve, which is one of the B & Bs in the pamphlet. It's a little farther away from the school - it's in Center City - but as someone else mentioned, its location gives you lots to do and see when you're not at the school. The subway that goes up Broad St. to Hahnemann Hosp. is a few blocks away, and there's a shuttle there that goes to the school.
Be warned though...although I took the shuttle a couple of times without any problems, I did kind of have to "talk my way onto" the shuttle, and a couple of current Drexel students have said that you're really supposed to have a pass to ride the shuttle. The pamphlets, although they say they're usable as your pass, are old and the policy has changed, again according to those students' posts.
The upside to riding the shuttle is that it gave me a chance to talk to other students who were riding it, which I found really helpful.