vittoria randonneur in the back and a conti 4000s up front. ive also used the GP 4 seasons and the Ultra Gator up front. they all rock.
ive ran a version of this combo over the last year and haven't had a flat yet.
the armadillos are also good tires but have a harsher ride. the armadillo elites are a bit nicer but i would skip them and just go for some contis