Hey, this thread finally got going!! 🙂
I'm not sure about what the concensus is regarding when to take the year off - some say between 2nd and 3rd, some say between 3rd and 4th. But, I definetely haven't heard about taking it between 4th and residency.
In any case, I think it really depends on what you want to do in that year. If you want to do something clinical, obviously taking off after third makes sense. But, if you want to do something that's not clinical (which is what Gabadoo and I seem to want) then I think it's better to take off after second year.
Personally, i'm applying for a program that would let me do 6 months of international public health work abroad. I won't know whether or not I got accepted until late march / early april, and I don't have a back-up plan, so i'm a little bit nervous about that. I'm also really interested in learning languages during that year off, but it seems that any sort of language study is expensive, unless you can combine it with some program abroad and take the language lessons on the side (that's my plan).