Daytonafan... who else do you think started the post? The user name 'Confused' is what gave the Clinton's secret identity away. (sorry, chappaqua- just kidding). Quick answer- there are a number of boilers with AFUE ratings in the 93/94% range depending on which model or size of the same model. I'd almost be willing to bet some German or Swedish models exceed that. With the proper applications, one can get amazing efficiencies with a modulating/ condensing (mod-con) boiler.
Don't confuse me with facts, my mind is already made up.