This happened to me. I took a semester off between 2nd and 3rd year for a family illness, started third year in Dec and graduated this Dec. I will begin residency in July of this year.
At the time, it was a tough decision to make, however, it turned out to be the BEST decision I have ever made in my life and, looking back, I can't imagine applying to residency on the regular track.
If you plot out your semesters, you will see that I had a full semester of fourth year BEFORE the application process began in July/Aug. That meant that I had more than enough elective time to explore subspecialties that I would not have had the elective time to explore. I also was able to set up my subI and other electives in order to have the strongest letters of rec that I could find. I ended up going for a competitive subspecialty that I would have never DREAMED of applying for three years previously. I took two weeks of it becasue I had no exposure to it in med school, fell in love with it, took a month elective in it, got a strong letter and applied.
I also decided to back up with another specialty, if I did not get in. As a result I did twice as much as any other applicant. I got 7 letters of rec total, wrote 2 PS, interviewed at 30 places! (1/2 one spec, 1/2 another, + a few prlims) I would never have been able to pull this off on the regular track.
So, it is my opinion that if you are not sure as to what you want to go into, it is a great decision to get off track and give yourself more time and opportunity. I could have done a bunch of research as well. In addition, I was NOT a strong applicant coming out of 2nd year, but I took step 2 super early (at the end of MY 3rd year, in Dec) got a strong grade, took CS, got double the clinical evals of other applicants, and in the end I matched at my first choice in the competitive specialty. I got 12 interviews in that field.
I spent all of this dec and jan traveling, no worries about days off (I took dec off so i actually ended in nov).
I WAS offered by my home school to start my prelim year early, but i had such a packed interview schedule into Jan, I did not want to do that.
I honestly have not had alot of down time, but starting next week, i have nothing to do until the end of June, (some prelim programs I applied to start June 15) so I am looking into international work.
I must add, however, that it is awkward not walking with your class. I graduated in Dec, and it was so anticlimactic, no ceremony, no party, nothin. But I will walk in May- with another class. all of my friend's are interns now, that is sorta weird, but I would never change my decision. Taking time off certainly set my career up well for the rest of my life.
good luck.