2009: Buenos Aires, Argentina. I actually can't
really comment on
this one; I believe one or two people were refused visas, but the fact
is that there isn't a single country on the planet that allows
citizens of all 195 countries (and other jurisdictions) hassle-free
entry.
Not that I want to support this thread any further (and I believe you as a
moderator could have already frozen it), but just to remark that as far as
I know there is a single country in the world which provides hassle-free
entry and hands in visa on arrival to visitors of any nationality. This is
Maldives.
Cheers
Yaroslav